N-substituted furfurylamines(FAs)are valuable precursors for producing pharmacologically active compounds and polymers.However,enzymatic synthesis of the type of chemicals is still in its infancy.Here we report an imi...N-substituted furfurylamines(FAs)are valuable precursors for producing pharmacologically active compounds and polymers.However,enzymatic synthesis of the type of chemicals is still in its infancy.Here we report an imine reductase from Streptomyces albidoflavus(SaIRED)for the reductive amination of biobased furans.A simple,fast and interference-resistant high-throughput screening(HTS)method was developed,based on the coloration reaction of carbonyl compounds with 2,4-dinitrophenylhydrazine.The reductive amination activity of IREDs can be directly indicated by a colorimetric assay.With the reductive amination of furfural with allylamine as the model reaction,SaIRED with the activity of 4.8 U mg^(-1) was subjected to three rounds of protein engineering and screening by this HTS method,affording a high-activity tri-variant I127V/D241A/A242T(named M3,20.2 U mg^(-1)).The variant M3 showed broad substrate scope,and enabled efficient reductive amination of biobased furans with a variety of amines including small aliphatic amines and sterically hindered amines,giving the target FAs in yields up to>99%.In addition,other variants were identified for preparative-scale synthesis of commercially interesting amines such as N-2-(methylsulfonyl)ethyl-FA by the screen method,with isolated yields up to 87%and turnover numbers up to 9700 for enzyme.Gram-scale synthesis of N-allyl-FA,a valuable building block and potential polymer monomer,was implemented at 0.25 mol L^(-1) substrate loading by a whole-cell catalyst incorporating variant M3,with 4.7 g L^(-1) h^(-1) space-time yield and 91%isolated yield.展开更多
Aldo-keto reductases(AKRs)are a superfamily of enzymes that play crucial roles in various cellular processes,including the metabolism of xenobiotics,steroids,and carbohydrates.A growing body of evidence has unveiled t...Aldo-keto reductases(AKRs)are a superfamily of enzymes that play crucial roles in various cellular processes,including the metabolism of xenobiotics,steroids,and carbohydrates.A growing body of evidence has unveiled the involvement of AKRs in the development and progression of various cancers.AKRs are aberrantly expressed in a wide range of malignant tumors.Dysregulated expression of AKRs enables the acquisition of hallmark traits of cancer by activating oncogenic signaling pathways and contributing to chemoresistance.AKRs have emerged as promising oncotherapeutic targets given their pivotal role in cancer development and progression.Inhibition of aldose reductase(AR),either alone or in combination with chemotherapeutic drugs,has evolved as a pragmatic therapeutic option for cancer.Several classes of synthetic aldo-keto reductase(AKR)inhibitors have been developed as potential anticancer agents,some of which have shown promise in clinical trials.Many AKR inhibitors from natural sources also exhibit anticancer effects.Small molecule inhibitors targeting specific AKR isoforms have shown promise in preclinical studies.These inhibitors disrupt the activation of oncogenic signaling by modulating transcription factors and kinases and sensitizing cancer cells to chemotherapy.In this review,we discuss the physiological functions of human AKRs,the aberrant expression of AKRs in malignancies,the involvement of AKRs in the acquisition of cancer hallmarks,and the role of AKRs in oncogenic signaling,and drug resistance.Finally,the potential of aldose reductase inhibitors(ARIs)as anticancer drugs is summarized.展开更多
Optically pure(R)-γ-and(R)-δ-lactones can be prepared by intramolecular cyclization of chiral hydroxy acids/esters reduced asymmetrically from γ-and δ-keto acids/esters using Saccharomyces cerevisiae(S.cerevisiae)...Optically pure(R)-γ-and(R)-δ-lactones can be prepared by intramolecular cyclization of chiral hydroxy acids/esters reduced asymmetrically from γ-and δ-keto acids/esters using Saccharomyces cerevisiae(S.cerevisiae) as a whole-cell biocatalyst.However,some of the enzymes catalyzing these reactions in S.cerevisiae are still unknown up to date.In this report,two carbonyl reductases,OdCRl and OdCR2,were successfully discovered,and cloned from S.cerevisiae using a genome-mining approach,and overexpressed in Escherichia coli(E.coli).Compared with OdCR1,OdCR2 can reduce 4-oxodecanoic acid and 5-oxodecanoic acid asymmetrically with higher stereoselectivity,generating(R)-γ-decalactone(99% ee) and(R)-δ-decalactone(98% ee) in 85% and 92%yields,respectively.This is the first report of native enzymes from S.cerevisiae for the enzymatic synthesis of chiral γ-and δ-lactones which is of wide uses in food and cosmetic industries.展开更多
Introduction One of the major root alkaloids of the Indian medicinal plant Rauvolfia serpenlina Benth. ex Kurz is named ajmaline. The enzymatic biosynthesis of this alkaloid has been studied for a long time by our gr...Introduction One of the major root alkaloids of the Indian medicinal plant Rauvolfia serpenlina Benth. ex Kurz is named ajmaline. The enzymatic biosynthesis of this alkaloid has been studied for a long time by our group As a result, a biosynthetic pathway has been established, in which about 10 enzymes participate, several of them belonging to the group of NADPH-dependent reductases. Started with the biosynthetic precursors tryptamine and secologanin,展开更多
The thermostability of three sulfur oxygenase reductases （SORs） was investigated from thermoacidophilic achaea Acidianus tengchongensis （SORAT） and Sulfolobus tokodaii （SORsT） as well as the moderately thermophi...The thermostability of three sulfur oxygenase reductases （SORs） was investigated from thermoacidophilic achaea Acidianus tengchongensis （SORAT） and Sulfolobus tokodaii （SORsT） as well as the moderately thermophilic bacterium Acidithiobacillus sp. SM-1 （SORsB）. The optimal temperatures for catalyzing sulfur oxidation were 80 ℃ （SORAT）, 85 ℃ （SORsT）, and 70 ℃ （SORsB）, respectively. The half-lives of the three SORs at their optimal catalytic conditions were 100 min （SORAT）, 58 min （SORsT）, and 37 min （SORsB）. In order to reveal the structural basis of the thermostability of these SORs, three-dimensional structural models of them were generated by homology modeling using the previously reported high-resolution X-ray structure of SORAA （from Acidianus ambivalens） as a template. The results suggest that thermostability was dependent on： （a） high number of the charged amino acid glutamic acid and the flexible amino acid proline, （b） low number of the therraolabile amino acid glutamine, （c） increased number of ion pairs, （d） decreased ratio of hydrophobie accessible solvent surface area （ASA） to charged ASA, and （e） increased volumes of the cavity. The number of cavities and the number of hydrogen bonds did not signifieantly affect the thermostability of SORs, whereas the cavity volumes increased as the thermal stability increased.展开更多
Ethyl(R)-4-chloro-3-hydroxybutyrate((R)-CHBE),as a chiral intermediate,is widely used in the synthesis of various chiral drugs.In this study,we screened two aldo–keto reductases(LP-AKRs)from the probiotic Lactobacill...Ethyl(R)-4-chloro-3-hydroxybutyrate((R)-CHBE),as a chiral intermediate,is widely used in the synthesis of various chiral drugs.In this study,we screened two aldo–keto reductases(LP-AKRs)from the probiotic Lactobacillus plantarum DSM20174,both with a molecular weight of approximately 31 kDa.Both enzymes could reduce 4-chloroacetoacetic acid ethyl ester(COBE)to produce(R)-CHBE with an enantioselectivity value of 99%.When determining the kinetic parameter,the K_(m),K_(cat),and V_(max)of LP-AKR5 and LP-AKR9 were 9.5 mM,7.6 U/mg,3.96 s^(-1)and 8.7 mM,8.59 U/mg,4.47 s^(-1),respectively.Both LP-AKR5 and LP-AKR9 had an optimal reaction pH of 6 and could maintain a high level of stability at pH 6,allowing them to perform well in an acidic environment.LP-AKR5 and LP-AKR9 had optimal reaction temperatures of 30℃and 40℃,respectively.Metal ions had minimal influence on LP-AKR5 and LP-AKR9 enzyme activities.This series of enzymatic properties showed that LP-AKR5 and LP-AKR9 mined from Lactobacillus plantarum DSM20174 could asym-metrically catalyze the synthesis of(R)-CHBE under weakly acidic circumstances,which could maintain product stability and provide a good foundation for industrial production.展开更多
Methionine oxidation to methionine sulfoxide （MetSO） is reversed by two types of methionine sulfoxide reducrases （MSRs）, A and B, specific to the S- and R-diastereomers of MetSO, respectively. MSR genes are found ...Methionine oxidation to methionine sulfoxide （MetSO） is reversed by two types of methionine sulfoxide reducrases （MSRs）, A and B, specific to the S- and R-diastereomers of MetSO, respectively. MSR genes are found in most organisms from bacteria to human. In the current review, we first compare the organization of the MSR gene families in photosynthetic organisms from cyanobacteria to higher plants. The analysis reveals that MSRs constitute complex families in higher plants, bryophytes, and algae compared to cyanobacteria and all non-photosynthetic organisms. We also perform a classification, based on gene number and structure, position of redox-active cysteines and predicted sub-cellular localization. The various catalytic mechanisms and potential physiological electron donors involved in the regeneration of MSR activity are then de- scribed. Data available from higher plants reveal that MSRs fulfill an essential physiological function during environmental constraints through a role in protein repair and in protection against oxidative damage. Taking into consideration the ex- pression patterns of MSR genes in plants and the known roles of these genes in non-photosynthetic cells, other functions of MSRs are discussed during specific developmental stages and ageing in photosynthetic organisms.展开更多
Mutations in the photorespiration pathway dis- play a lethal phenotype in atmospheric air, which can be fully recovered by elevated C02. An exception is that mutants of peroxisomal hydroxypyruvate reductase （HPR1） d...Mutations in the photorespiration pathway dis- play a lethal phenotype in atmospheric air, which can be fully recovered by elevated C02. An exception is that mutants of peroxisomal hydroxypyruvate reductase （HPR1） do not have this phenotype, indicating the presence of cytosolic bypass in the photorespiration pathway. In this study, we constructed overexpression of the OsHPR1 gene and RNA interference plants of OsHPR1 and OsHPR2 genes in rice （Oryza sativo L. cv. Zhonghua 11）. Results from reverse transcription-polymerase chain reaction （RT-PCR）, Western blot, and enzyme assays showed that HPR1 activity changed significantly in corresponding transgenic lines without any effect on HPR2 activity, which is the same for HPR2. However, metabolite analysis and the serine glyoxylate aminotransferase （SGAT） activity assay showed that the metabolite flux of photorespiration was disturbed in RNAi lines of both HPR genes. Furthermore, HPR1 and HPR2 proteins were located to the peroxisome and cytosol, respectively, by transient expression experiment. Double mutant hprl x hpr2 was generated by crossing individual mutant of hprl and hpr2. The phenotypes of all transgenic lines were determined in ambient air and C02-elevated air. The phenotype typical of photorespiration mutants was observed only where activity of both HPRI and HPR2 were downregulated in the same line. These findings demonstrate that two hydroxypyruvate reductases encoded by OsHPRI and OsHPR2 are involved in photorespiratory metabolism in rice.展开更多
Nitric oxide reductases(NORs)have a central role in denitrification,detoxification of nitric oxide(NO)in host-pathogen interactions,and NO-mediated cell-cell signaling.In this study,we focus on the phylogeny and detec...Nitric oxide reductases(NORs)have a central role in denitrification,detoxification of nitric oxide(NO)in host-pathogen interactions,and NO-mediated cell-cell signaling.In this study,we focus on the phylogeny and detection of qNOR and cNOR genes because of their nucleotide sequence similarity and evolutionary relatedness to cytochrome oxidases,their key role in denitrification,and their abundance in natural,agricultural,and wastewater ecosystems.We also include nitric oxide dismutase(NOD)due to its similarity to qNOR.Using 548 nor sequences from publicly accessible databases and sequenced isolates from N2O-producng bioreactors,we constructed phylogenetic trees for 289 qnor/nod genes and 259 cnorB genes.These trees contain evidence of horizontal gene transfer and gene duplication,with 13.4%of the sequenced strains containing two or more nor genes.By aligning amino acid sequences for qnor+cnor,qnor,and cnor,we identified four highly conserved regions for NOR and NOD,including two highly conserved histidine residues at the active site for qNOR and cNOR.Extending this approach,we identified conserved sequences for:1)all nor(nor-universal);2)all qnor(qnor-universal)and all cnor(cnor-universal);3)qnor of Comamonadaceae;4)Clade-specific sequences;and 5)nod of Candidates Methylomirabilis oxyfera.Examples of primer performance were confirmed experimentally.展开更多
As a versatile type of enzyme,carboxylic acid reductases(CAR)can not only reduce various carboxylic acids to aldehydes in cooperation with cofactors ATP and NADPH but also catalyze the synthesis of amides and esters i...As a versatile type of enzyme,carboxylic acid reductases(CAR)can not only reduce various carboxylic acids to aldehydes in cooperation with cofactors ATP and NADPH but also catalyze the synthesis of amides and esters in the absence of NADPH.Here,we report an intramolecular cyclization catalyzed by CAR only with the use of ATP to transform amino acids into diverse lactams,includingγ-/δ-/ε-lactams and chiral derivatives thereof.The observed wide substrate scope and selectivity enable potential applications to be implemented.Our results demonstrate that CAR-catalyzed lactamization is a promising approach for the synthesis of chiral lactam com-pounds under mild conditions,thereby enriching the toolbox for the biosynthesis of lactams as a viable alternative to purely chemical procedures.展开更多
Mining and tailings deposition can cause serious heavy metal(loids)pollution to the surrounding soil environment.Soil microorganisms adapt their metabolism to such conditions,driving alterations in soil function.This ...Mining and tailings deposition can cause serious heavy metal(loids)pollution to the surrounding soil environment.Soil microorganisms adapt their metabolism to such conditions,driving alterations in soil function.This study aims to elucidate the response patterns of nitrogen-cycling microorganisms under long-term heavy metal(loids)exposure.The results showed that the diversity and abundance of nitrogen-cyclingmicroorganisms showed negative feedback to heavy metal(loids)concentrations.Denitrifying microorganisms were shown to be the dominant microorganisms with over 60%of relative abundance and a complex community structure including 27 phyla.Further,the key bacterial species in the denitrification process were calculated using a random forest model,where the top three key species(Pseudomonas stutzei,Sphingobium japonicum and Leifsonia rubra)were found to play a prominent role in nitrite reduction.Functional gene analysis and qPCR revealed that nirK,which is involved in nitrite reduction,significantly accumulated in the most metal-rich soil with the increase of absolute abundance of 63.86%.The experimental results confirmed that the activity of nitrite reductase(Nir)encoded by nirK in the soil was increased at high concentrations of heavy metal(loids).Partial least squares-path model identified three potential modes of nitrite reduction processes being stimulated by heavy metal(loids),the most prominent of which contributed to enhanced nirK abundance and soil Nir activity through positive stimulation of key species.The results provide new insights and preliminary evidence on the stimulation of nitrite reduction processes by heavy metal(loids).展开更多
Surgical intervention is currently the primary treatment for hepatolithiasis;how-ever,some patients still experience residual stones and high recurrence rates after surgery.Cholesterol metabolism seems to play an impo...Surgical intervention is currently the primary treatment for hepatolithiasis;how-ever,some patients still experience residual stones and high recurrence rates after surgery.Cholesterol metabolism seems to play an important role in hepatoli-thiasis pathogenesis.A high cholesterol diet is one of the significant reasons for the increasing incidence of hepatolithiasis.Therefore,regular diet and appropriate medical intervention are crucial measures to prevent hepatolithiasis and reduce recurrence rate after surgery.Reducing dietary cholesterol and drugs that increase cholesterol stone solubility are key therapeutic approaches in treating hepato-lithiasis.This article discusses the cholesterol metabolic pathways related to the pathogenesis of hepatolithiasis,as well as food intake and targeted therapeutic drugs.展开更多
Folic acid(FA)deficiency during pregnancy is a significant risk factor for neural tube defects in infants.Appropriate supplementation with FA has been shown to effectively mitigate the risk of such congenital anomalie...Folic acid(FA)deficiency during pregnancy is a significant risk factor for neural tube defects in infants.Appropriate supplementation with FA has been shown to effectively mitigate the risk of such congenital anomalies.However,genetic polymorphisms related to FA metabolism influence individual variations in FA utilization among pregnant women,highlighting the need for personalized supplementation strategies.This study aimed to explore the impact of genetic variations in FA metabolism-related genes,specifically methylenetetrahydrofolate reductase(MTHFR)and methionine synthase reductase(MTRR),on tailoring FA supplementation during pregnancy.Using fluorescence hybridization sequencing,we analyzed polymorphisms in the MTHFR and MTRR genes among 694 pregnant women,who were divided into an individualized supplementation group and a control group.Pregnancy outcomes were monitored through outpatient visits and telephone follow-ups to evaluate the effect of personalized FA supplementation guided by genetic profiling.Notable differences in genotype frequencies of MTHFR(rs1801133,rs1801131)and MTRR(rs1801394)were observed between pregnant women with and without a heightened risk of FA metabolism disorders(P<0.05).Similarly,allele frequencies of MTHFR(rs1801133)and MTRR(rs1801394)varied significantly among women with different risk profiles(P<0.05).The results demonstrated that the individualized group exhibited significantly lower incidences of birth defects,preterm delivery,spontaneous abortion,premature rupture of membranes,abnormal amniotic fluid,and gestational hypertension compared to the control group(P<0.05).These findings suggested that polymorphisms in MTHFR and MTRR genes were key determinants of FA metabolism and might contribute to adverse pregnancy outcomes in populations with a high prevalence of FA metabolism disorders.Furthermore,integrating genetic screening into FA supplementation protocols enabled more effective prevention of pregnancy complications and improved overall maternal and fetal health outcomes.展开更多
Microbial selenite(Se(Ⅳ)) reduction to elemental selenium nanoparticles(SeNPs) and chromate(Cr(Ⅵ)) remediation constitute effective detoxification processes. The strain Bacillus wiedmannii ES2-45 can efficiently red...Microbial selenite(Se(Ⅳ)) reduction to elemental selenium nanoparticles(SeNPs) and chromate(Cr(Ⅵ)) remediation constitute effective detoxification processes. The strain Bacillus wiedmannii ES2-45 can efficiently reduce 5 mmol/L Se(Ⅳ) into SeNPs over 14 h and 1 mmol/L Cr(Ⅵ) within 36 h. Proteomic analysis and qRT-PCR revealed that reductases, including dithiol oxidoreductase(DsbA), Fe-S biosynthesis domain-containing protein(Fes),and aldose-6-phosphate reductase(Aldo), and bacillithiol(BSH) were involved in Se(Ⅳ) reduction. Heterologous expression further confirmed the Se(Ⅳ)-reducing function of three genes and enhanced the Se(Ⅳ) and Cr(Ⅵ) resistance ability. Moreover, the difference between Se(Ⅳ) treatments and controls both intra-and extra-cellular BSH concentration per biomass indicated that BSH contributes to Se(Ⅳ) reduction. Selenium-fortified rice was obtained by foliar spray of SeNPs synthesized by the strain ES2-45. To the best of our knowledge, DsbA and Aldo reductase were firstly verified for the role in Se(Ⅳ) reduction and Cr(Ⅵ)resistance. Importantly, it is a promising strategy that B. wiedmannii ES2-45 is served as an efficient bacterium for SeNP synthesis, selenium biofortification and heavy metal bioremediation.展开更多
This letter critically comments on the article by Zheng et al investigating the role of aucubin in alleviating diabetic neuropathic pain(DNP).DNP arises from hyperglycaemia-induced nerve injury and microglial reprogra...This letter critically comments on the article by Zheng et al investigating the role of aucubin in alleviating diabetic neuropathic pain(DNP).DNP arises from hyperglycaemia-induced nerve injury and microglial reprogramming toward aerobic glycolysis.Aldose reductase(also known as AKR1B1)redirects excess glucose flux through the polyol pathway,thus increasing oxidative stress and inflammation.Zheng et al show that aucubin,a plant iridoid glycoside,reverses streptozotocin-induced mechanical and thermal hypersensitivity and anxiety-like behaviour in mice.Mechanistically,aucubin restores microglial morphology,reduces glycolytic flux,enhances oxidative phosphorylation and lowers tumour necrosis factor-α,interleukin(IL)-1βand IL-6 levels in spinal tissue and cultures of the BV-2 microglial cell line.Network pharmacology and molecular docking analyses identify AKR1B1 as a key target,confirmed by the fact that short hairpin RNA knockdown of AKR1B1 eliminates the effects of aucubin.Contrary to the other studies,this study uniquely implicates the polyol pathway in microglial immunometabolism.展开更多
Sennoside A(SA),a typical prodrug,exerts its laxative effect only after its transformation into rheinanthrone catalyzed by gut microbial hydrolases and reductases.Hydrolases have been identified,but reductases remain ...Sennoside A(SA),a typical prodrug,exerts its laxative effect only after its transformation into rheinanthrone catalyzed by gut microbial hydrolases and reductases.Hydrolases have been identified,but reductases remain unknown.By linking a photoreactive group to the SA scaffold,we synthesized a photoaffinity probe to covalently label SA reductases and identified SA reductases using activity-based protein profiling(ABPP).From lysates of an active strain,Bifidobacterium pseudocatenulatum(B.pseudocatenulatum),397 proteins were enriched and subsequently identified using mass spectrometry(MS).Among these proteins,chromate reductase/nicotinamide adenine dinucleotide(NADH)phosphate(NADPH)-dependent flavin mononucleotide(FMN)reductase/oxygen-insensitive NADPH nitroreductase(nfrA)was identified as a potent SA reductase through further bioinformatic analysis and The Universal Protein Resource(UniProt)database screening.We also determined that recombinant nfrA could reduce SA.Our study contributes to further illuminating mechanisms of SA transformation to rheinanthrone and simultaneously offers an effective method to identify gut bacterial reductases.展开更多
BACKGROUND Treatment of diabetic neuropathy is often limited by side effects.Aucubin,an iridoid glycoside derived from natural plants,exhibits notable anti-inflammatory and antioxidant properties.AIM To investigate th...BACKGROUND Treatment of diabetic neuropathy is often limited by side effects.Aucubin,an iridoid glycoside derived from natural plants,exhibits notable anti-inflammatory and antioxidant properties.AIM To investigate the effects of aucubin on diabetic neuropathic pain(DNP)and glycolysis and inflammation in microglia.METHODS Streptozotocin(STZ)was used to establish a DNP animal model.Blood glucose levels and body weight of mice were measured following STZ administration.Paw withdrawal threshold was calculated for mechanical allodynia.Paw withdrawal latency was recorded for thermal hyperalgesia.The open field test and elevated plus maze was used to assess locomotor activity and anxiety-like behavior.Western blotting was utilized for analysis of protein expression.Immunofluorescence staining was measured for morphometric analysis of microglia.Glycolysis and ATP synthesis in BV-2 cell lines were detected by metabolic extracellular flux analysis.The SwissTargetPrediction and STRING databases were used for comprehensive screening to identify potential target proteins for aucubin.The molecular docking between the possible target proteins and aucubin was investigated using Auto Dock Tool.The BV-2 cell line was transfected with lentiviral AKR1B1-shRNA to further ascertain the function of AKR1B1 in the impact of aucubin on aerobic glycolysis and inflammation during high glucose stimulation.RESULTS Aucubin significantly improved pain and anxiety-like behavior in STZ-induced diabetic mice and restored microglial aerobic glycolysis and inflammation.Several public databases and molecular docking studies suggested that AKR1B1,MMP2 and MMP9 are involved in the effect of aucubin on DNP.Aucubin failed to restore aerobic glycolysis and inflammation in the context of AKR1B1 deficiency.CONCLUSION Aucubin has potential as a therapeutic agent for alleviating DNP by inhibiting expression of AKR1B1.展开更多
Ulva prolifera,the primary causative species of green tide,has garnered significant attention due to its robust growth and reproductive capacity under high salt stress.However,there has been relatively little research...Ulva prolifera,the primary causative species of green tide,has garnered significant attention due to its robust growth and reproductive capacity under high salt stress.However,there has been relatively little research on the regulation of high salt stress in this species.In this study,we observed that high salt stress suppressed the growth of U.prolifera and leading to the nitric oxide(NO)accumulation,along with increased gene expression levels and enzyme activity of S-nitrosoglutathione reductase(GSNOR).Treatment with GSNOR inhibitor resulted in elevated NO levels under high salt stress,accompanied by reduced activity of antioxidant enzymes and decreased glutathione(GSH)accumulation,making U.prolifera more sensitive to high salt stress.Conversely,NO scavenger treatment not only reduced NO levels,but also weakened the high salt stress tolerance of U.prolifera.Furthermore,using tandem mass tags(TMT)switch analysis and mass spectrometry,we observed a significant increase in S nitrosylated protein levels in U.prolifera under high salt stress,with further augmentation upon GSNOR inhibitor treatment.We also found high salt stress induced S-nitrosylation(SNO)of glutathione reductase(GR),which is negatively regulated by GSNOR,resulting in increased GR activity.Our results show that under short-term high salt stress,the elevated expression level of GSNOR avoided excessive accumulation of NO,and a certain amount of NO enhanced the activity of antioxidant enzymes through SNO modification,which improve the high salt stress tolerance of U.prolifera,whereas under long-term high salt stress,excessive NO was toxic to U.prolifera.展开更多
Selenium(Se),an essential micronutrient among the 15 vital elements required for human physiology,exerts its biological functions primarily through its incorporation into selenoproteins.To date,approximately 25 seleno...Selenium(Se),an essential micronutrient among the 15 vital elements required for human physiology,exerts its biological functions primarily through its incorporation into selenoproteins.To date,approximately 25 selenoproteins have been characterized in mammalian systems,including glutathione peroxidase(GPX),thioredoxin reductase(TrxR),and iodothyronine deiodinases(DIOs),all of which exhibit indispensable physiological functions.展开更多
Chiral N-substituted amino amides and esters are ubiquitous scaffolds in pesticides and pharmaceutical chemicals,but their asymmetric synthesis remains challenging especially for those with multiple chiral centers.In ...Chiral N-substituted amino amides and esters are ubiquitous scaffolds in pesticides and pharmaceutical chemicals,but their asymmetric synthesis remains challenging especially for those with multiple chiral centers.In this study,IR104 from Streptomyces aureocirculatus was identified from 157 wild-type imine reductases for the synthesis of(S)-2-((R)-2-oxo-4-propylpyrrolidin-1-yl)butanamide(antiepileptic drug Brivaracetam)via dynamic kinetic resolution reductive amination from ethyl 3-formylhexanoate and(S)-2-aminobutylamide with high diastereoselectivity.To further improve the catalytic efficiency of IR104,its mutant D191E/L195I/E253S/M258A(M3)was identified by saturation mutagenesis and iterative combinatorial mutagenesis,which exhibited a 102-fold increase in the catalytic efficiency relative to that of wild-type enzyme and high diastereoselectivity(98:2 d.r.).Crystal structural analysis and molecular dynamics simulations provided some insights into the molecular basis for the improved activity of the mutant enzyme.The imine reductase identified in this study could accept chiral amino amides/esters as amino donors for the dynamic kinetic resolution reductive amination of racemicα-substituted aldehydo-esters,expanding the substrate scope of imine reductases in the dynamic kinetic resolution-reductive amination.Finally,IR104-M3 was successfully used for the preparation of Brivaracetam at gram scale.Using this mutant,various N-substituted amino amides/esters with two chiral centers were also synthesized with up to 99:1 d.r.and 96%yields and subsequently converted intoγ-andδ-lactams,providing an efficient protocol for the synthesis of these important compounds via enzymatic dynamic kinetic resolution-reductive amination from simple building blocks.展开更多
文摘N-substituted furfurylamines(FAs)are valuable precursors for producing pharmacologically active compounds and polymers.However,enzymatic synthesis of the type of chemicals is still in its infancy.Here we report an imine reductase from Streptomyces albidoflavus(SaIRED)for the reductive amination of biobased furans.A simple,fast and interference-resistant high-throughput screening(HTS)method was developed,based on the coloration reaction of carbonyl compounds with 2,4-dinitrophenylhydrazine.The reductive amination activity of IREDs can be directly indicated by a colorimetric assay.With the reductive amination of furfural with allylamine as the model reaction,SaIRED with the activity of 4.8 U mg^(-1) was subjected to three rounds of protein engineering and screening by this HTS method,affording a high-activity tri-variant I127V/D241A/A242T(named M3,20.2 U mg^(-1)).The variant M3 showed broad substrate scope,and enabled efficient reductive amination of biobased furans with a variety of amines including small aliphatic amines and sterically hindered amines,giving the target FAs in yields up to>99%.In addition,other variants were identified for preparative-scale synthesis of commercially interesting amines such as N-2-(methylsulfonyl)ethyl-FA by the screen method,with isolated yields up to 87%and turnover numbers up to 9700 for enzyme.Gram-scale synthesis of N-allyl-FA,a valuable building block and potential polymer monomer,was implemented at 0.25 mol L^(-1) substrate loading by a whole-cell catalyst incorporating variant M3,with 4.7 g L^(-1) h^(-1) space-time yield and 91%isolated yield.
基金SN and GBR are supported by grants from the Science and Engineering Research Board,Government of India(EMR/2016/001984)Indian Council of Medical Research.
文摘Aldo-keto reductases(AKRs)are a superfamily of enzymes that play crucial roles in various cellular processes,including the metabolism of xenobiotics,steroids,and carbohydrates.A growing body of evidence has unveiled the involvement of AKRs in the development and progression of various cancers.AKRs are aberrantly expressed in a wide range of malignant tumors.Dysregulated expression of AKRs enables the acquisition of hallmark traits of cancer by activating oncogenic signaling pathways and contributing to chemoresistance.AKRs have emerged as promising oncotherapeutic targets given their pivotal role in cancer development and progression.Inhibition of aldose reductase(AR),either alone or in combination with chemotherapeutic drugs,has evolved as a pragmatic therapeutic option for cancer.Several classes of synthetic aldo-keto reductase(AKR)inhibitors have been developed as potential anticancer agents,some of which have shown promise in clinical trials.Many AKR inhibitors from natural sources also exhibit anticancer effects.Small molecule inhibitors targeting specific AKR isoforms have shown promise in preclinical studies.These inhibitors disrupt the activation of oncogenic signaling by modulating transcription factors and kinases and sensitizing cancer cells to chemotherapy.In this review,we discuss the physiological functions of human AKRs,the aberrant expression of AKRs in malignancies,the involvement of AKRs in the acquisition of cancer hallmarks,and the role of AKRs in oncogenic signaling,and drug resistance.Finally,the potential of aldose reductase inhibitors(ARIs)as anticancer drugs is summarized.
基金financially sponsored by the National Key Research and Development Program of China (2016YFA0204300, 2019YFA09005000)the National Natural Science Foundation of China (21536004, 21776085, 21871085)+2 种基金the Natural Science Foundation of Shanghai (18ZR1409900)Key Project of the Shanghai Science and Technology Committee (18DZ1112703)the Fundamental Research Funds for the Central Universities (WF1714026)。
文摘Optically pure(R)-γ-and(R)-δ-lactones can be prepared by intramolecular cyclization of chiral hydroxy acids/esters reduced asymmetrically from γ-and δ-keto acids/esters using Saccharomyces cerevisiae(S.cerevisiae) as a whole-cell biocatalyst.However,some of the enzymes catalyzing these reactions in S.cerevisiae are still unknown up to date.In this report,two carbonyl reductases,OdCRl and OdCR2,were successfully discovered,and cloned from S.cerevisiae using a genome-mining approach,and overexpressed in Escherichia coli(E.coli).Compared with OdCR1,OdCR2 can reduce 4-oxodecanoic acid and 5-oxodecanoic acid asymmetrically with higher stereoselectivity,generating(R)-γ-decalactone(99% ee) and(R)-δ-decalactone(98% ee) in 85% and 92%yields,respectively.This is the first report of native enzymes from S.cerevisiae for the enzymatic synthesis of chiral γ-and δ-lactones which is of wide uses in food and cosmetic industries.
文摘Introduction One of the major root alkaloids of the Indian medicinal plant Rauvolfia serpenlina Benth. ex Kurz is named ajmaline. The enzymatic biosynthesis of this alkaloid has been studied for a long time by our group As a result, a biosynthetic pathway has been established, in which about 10 enzymes participate, several of them belonging to the group of NADPH-dependent reductases. Started with the biosynthetic precursors tryptamine and secologanin,
基金Supported by the National Natural Science Foundation of China (31070042,30870039,30921065)partially by Open Funding Project of the National Key Laboratory of Biochemical Engineering,China (2010KF-2)
文摘The thermostability of three sulfur oxygenase reductases （SORs） was investigated from thermoacidophilic achaea Acidianus tengchongensis （SORAT） and Sulfolobus tokodaii （SORsT） as well as the moderately thermophilic bacterium Acidithiobacillus sp. SM-1 （SORsB）. The optimal temperatures for catalyzing sulfur oxidation were 80 ℃ （SORAT）, 85 ℃ （SORsT）, and 70 ℃ （SORsB）, respectively. The half-lives of the three SORs at their optimal catalytic conditions were 100 min （SORAT）, 58 min （SORsT）, and 37 min （SORsB）. In order to reveal the structural basis of the thermostability of these SORs, three-dimensional structural models of them were generated by homology modeling using the previously reported high-resolution X-ray structure of SORAA （from Acidianus ambivalens） as a template. The results suggest that thermostability was dependent on： （a） high number of the charged amino acid glutamic acid and the flexible amino acid proline, （b） low number of the therraolabile amino acid glutamine, （c） increased number of ion pairs, （d） decreased ratio of hydrophobie accessible solvent surface area （ASA） to charged ASA, and （e） increased volumes of the cavity. The number of cavities and the number of hydrogen bonds did not signifieantly affect the thermostability of SORs, whereas the cavity volumes increased as the thermal stability increased.
文摘Ethyl(R)-4-chloro-3-hydroxybutyrate((R)-CHBE),as a chiral intermediate,is widely used in the synthesis of various chiral drugs.In this study,we screened two aldo–keto reductases(LP-AKRs)from the probiotic Lactobacillus plantarum DSM20174,both with a molecular weight of approximately 31 kDa.Both enzymes could reduce 4-chloroacetoacetic acid ethyl ester(COBE)to produce(R)-CHBE with an enantioselectivity value of 99%.When determining the kinetic parameter,the K_(m),K_(cat),and V_(max)of LP-AKR5 and LP-AKR9 were 9.5 mM,7.6 U/mg,3.96 s^(-1)and 8.7 mM,8.59 U/mg,4.47 s^(-1),respectively.Both LP-AKR5 and LP-AKR9 had an optimal reaction pH of 6 and could maintain a high level of stability at pH 6,allowing them to perform well in an acidic environment.LP-AKR5 and LP-AKR9 had optimal reaction temperatures of 30℃and 40℃,respectively.Metal ions had minimal influence on LP-AKR5 and LP-AKR9 enzyme activities.This series of enzymatic properties showed that LP-AKR5 and LP-AKR9 mined from Lactobacillus plantarum DSM20174 could asym-metrically catalyze the synthesis of(R)-CHBE under weakly acidic circumstances,which could maintain product stability and provide a good foundation for industrial production.
文摘Methionine oxidation to methionine sulfoxide （MetSO） is reversed by two types of methionine sulfoxide reducrases （MSRs）, A and B, specific to the S- and R-diastereomers of MetSO, respectively. MSR genes are found in most organisms from bacteria to human. In the current review, we first compare the organization of the MSR gene families in photosynthetic organisms from cyanobacteria to higher plants. The analysis reveals that MSRs constitute complex families in higher plants, bryophytes, and algae compared to cyanobacteria and all non-photosynthetic organisms. We also perform a classification, based on gene number and structure, position of redox-active cysteines and predicted sub-cellular localization. The various catalytic mechanisms and potential physiological electron donors involved in the regeneration of MSR activity are then de- scribed. Data available from higher plants reveal that MSRs fulfill an essential physiological function during environmental constraints through a role in protein repair and in protection against oxidative damage. Taking into consideration the ex- pression patterns of MSR genes in plants and the known roles of these genes in non-photosynthetic cells, other functions of MSRs are discussed during specific developmental stages and ageing in photosynthetic organisms.
基金supported by the National Natural Science Foundation of China (U1201212 31170222)+1 种基金the Shenzhen Overseas Talents Innovation and Entrepreneurship Funding Scheme (The Peacock Scheme)China Postdoctoral Science Foundation (2013M530374)
文摘Mutations in the photorespiration pathway dis- play a lethal phenotype in atmospheric air, which can be fully recovered by elevated C02. An exception is that mutants of peroxisomal hydroxypyruvate reductase （HPR1） do not have this phenotype, indicating the presence of cytosolic bypass in the photorespiration pathway. In this study, we constructed overexpression of the OsHPR1 gene and RNA interference plants of OsHPR1 and OsHPR2 genes in rice （Oryza sativo L. cv. Zhonghua 11）. Results from reverse transcription-polymerase chain reaction （RT-PCR）, Western blot, and enzyme assays showed that HPR1 activity changed significantly in corresponding transgenic lines without any effect on HPR2 activity, which is the same for HPR2. However, metabolite analysis and the serine glyoxylate aminotransferase （SGAT） activity assay showed that the metabolite flux of photorespiration was disturbed in RNAi lines of both HPR genes. Furthermore, HPR1 and HPR2 proteins were located to the peroxisome and cytosol, respectively, by transient expression experiment. Double mutant hprl x hpr2 was generated by crossing individual mutant of hprl and hpr2. The phenotypes of all transgenic lines were determined in ambient air and C02-elevated air. The phenotype typical of photorespiration mutants was observed only where activity of both HPRI and HPR2 were downregulated in the same line. These findings demonstrate that two hydroxypyruvate reductases encoded by OsHPRI and OsHPR2 are involved in photorespiratory metabolism in rice.
基金supported in part by a grant from the US National Science Foundation Engineering Research Center Reinventing the Nation's Urban Water Infrastructure(ReNUWIt)(Award No.EEC-1028968)in part by a grant from the NASA Center(USA)for the Utilization of Biological Engineering in Space(CUBES)(Award No.NNX17AJ31G).
文摘Nitric oxide reductases(NORs)have a central role in denitrification,detoxification of nitric oxide(NO)in host-pathogen interactions,and NO-mediated cell-cell signaling.In this study,we focus on the phylogeny and detection of qNOR and cNOR genes because of their nucleotide sequence similarity and evolutionary relatedness to cytochrome oxidases,their key role in denitrification,and their abundance in natural,agricultural,and wastewater ecosystems.We also include nitric oxide dismutase(NOD)due to its similarity to qNOR.Using 548 nor sequences from publicly accessible databases and sequenced isolates from N2O-producng bioreactors,we constructed phylogenetic trees for 289 qnor/nod genes and 259 cnorB genes.These trees contain evidence of horizontal gene transfer and gene duplication,with 13.4%of the sequenced strains containing two or more nor genes.By aligning amino acid sequences for qnor+cnor,qnor,and cnor,we identified four highly conserved regions for NOR and NOD,including two highly conserved histidine residues at the active site for qNOR and cNOR.Extending this approach,we identified conserved sequences for:1)all nor(nor-universal);2)all qnor(qnor-universal)and all cnor(cnor-universal);3)qnor of Comamonadaceae;4)Clade-specific sequences;and 5)nod of Candidates Methylomirabilis oxyfera.Examples of primer performance were confirmed experimentally.
基金supported by the National Key Research and Development Program of China(No.2019YFA0905100)the National Natural Science Foundation of China(No.31900909)+1 种基金the Natural Science Foundation Applying a system of Tianjin(No.21JCJQJC00110)and Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project(No.TSBICIP-CXRC-009)Mr Qu also thanks financial support from Youth Innovation Promotion Association,CAS(No.2021175).
文摘As a versatile type of enzyme,carboxylic acid reductases(CAR)can not only reduce various carboxylic acids to aldehydes in cooperation with cofactors ATP and NADPH but also catalyze the synthesis of amides and esters in the absence of NADPH.Here,we report an intramolecular cyclization catalyzed by CAR only with the use of ATP to transform amino acids into diverse lactams,includingγ-/δ-/ε-lactams and chiral derivatives thereof.The observed wide substrate scope and selectivity enable potential applications to be implemented.Our results demonstrate that CAR-catalyzed lactamization is a promising approach for the synthesis of chiral lactam com-pounds under mild conditions,thereby enriching the toolbox for the biosynthesis of lactams as a viable alternative to purely chemical procedures.
基金supported by the National Natural Science Foundation of China(No.41977029).
文摘Mining and tailings deposition can cause serious heavy metal(loids)pollution to the surrounding soil environment.Soil microorganisms adapt their metabolism to such conditions,driving alterations in soil function.This study aims to elucidate the response patterns of nitrogen-cycling microorganisms under long-term heavy metal(loids)exposure.The results showed that the diversity and abundance of nitrogen-cyclingmicroorganisms showed negative feedback to heavy metal(loids)concentrations.Denitrifying microorganisms were shown to be the dominant microorganisms with over 60%of relative abundance and a complex community structure including 27 phyla.Further,the key bacterial species in the denitrification process were calculated using a random forest model,where the top three key species(Pseudomonas stutzei,Sphingobium japonicum and Leifsonia rubra)were found to play a prominent role in nitrite reduction.Functional gene analysis and qPCR revealed that nirK,which is involved in nitrite reduction,significantly accumulated in the most metal-rich soil with the increase of absolute abundance of 63.86%.The experimental results confirmed that the activity of nitrite reductase(Nir)encoded by nirK in the soil was increased at high concentrations of heavy metal(loids).Partial least squares-path model identified three potential modes of nitrite reduction processes being stimulated by heavy metal(loids),the most prominent of which contributed to enhanced nirK abundance and soil Nir activity through positive stimulation of key species.The results provide new insights and preliminary evidence on the stimulation of nitrite reduction processes by heavy metal(loids).
基金Supported by Hebei Natural Science Foundation,No.H2022206539Hebei Provincial Government Funded Clinical Talents Training Project,No.ZF2023143.
文摘Surgical intervention is currently the primary treatment for hepatolithiasis;how-ever,some patients still experience residual stones and high recurrence rates after surgery.Cholesterol metabolism seems to play an important role in hepatoli-thiasis pathogenesis.A high cholesterol diet is one of the significant reasons for the increasing incidence of hepatolithiasis.Therefore,regular diet and appropriate medical intervention are crucial measures to prevent hepatolithiasis and reduce recurrence rate after surgery.Reducing dietary cholesterol and drugs that increase cholesterol stone solubility are key therapeutic approaches in treating hepato-lithiasis.This article discusses the cholesterol metabolic pathways related to the pathogenesis of hepatolithiasis,as well as food intake and targeted therapeutic drugs.
基金Key Laboratory Construction and Operation Project of Qinzhou Science and Technology Bureau(Grant No.20242422).
文摘Folic acid(FA)deficiency during pregnancy is a significant risk factor for neural tube defects in infants.Appropriate supplementation with FA has been shown to effectively mitigate the risk of such congenital anomalies.However,genetic polymorphisms related to FA metabolism influence individual variations in FA utilization among pregnant women,highlighting the need for personalized supplementation strategies.This study aimed to explore the impact of genetic variations in FA metabolism-related genes,specifically methylenetetrahydrofolate reductase(MTHFR)and methionine synthase reductase(MTRR),on tailoring FA supplementation during pregnancy.Using fluorescence hybridization sequencing,we analyzed polymorphisms in the MTHFR and MTRR genes among 694 pregnant women,who were divided into an individualized supplementation group and a control group.Pregnancy outcomes were monitored through outpatient visits and telephone follow-ups to evaluate the effect of personalized FA supplementation guided by genetic profiling.Notable differences in genotype frequencies of MTHFR(rs1801133,rs1801131)and MTRR(rs1801394)were observed between pregnant women with and without a heightened risk of FA metabolism disorders(P<0.05).Similarly,allele frequencies of MTHFR(rs1801133)and MTRR(rs1801394)varied significantly among women with different risk profiles(P<0.05).The results demonstrated that the individualized group exhibited significantly lower incidences of birth defects,preterm delivery,spontaneous abortion,premature rupture of membranes,abnormal amniotic fluid,and gestational hypertension compared to the control group(P<0.05).These findings suggested that polymorphisms in MTHFR and MTRR genes were key determinants of FA metabolism and might contribute to adverse pregnancy outcomes in populations with a high prevalence of FA metabolism disorders.Furthermore,integrating genetic screening into FA supplementation protocols enabled more effective prevention of pregnancy complications and improved overall maternal and fetal health outcomes.
基金supported by the National Natural Science Foundation of China(No.32370130).
文摘Microbial selenite(Se(Ⅳ)) reduction to elemental selenium nanoparticles(SeNPs) and chromate(Cr(Ⅵ)) remediation constitute effective detoxification processes. The strain Bacillus wiedmannii ES2-45 can efficiently reduce 5 mmol/L Se(Ⅳ) into SeNPs over 14 h and 1 mmol/L Cr(Ⅵ) within 36 h. Proteomic analysis and qRT-PCR revealed that reductases, including dithiol oxidoreductase(DsbA), Fe-S biosynthesis domain-containing protein(Fes),and aldose-6-phosphate reductase(Aldo), and bacillithiol(BSH) were involved in Se(Ⅳ) reduction. Heterologous expression further confirmed the Se(Ⅳ)-reducing function of three genes and enhanced the Se(Ⅳ) and Cr(Ⅵ) resistance ability. Moreover, the difference between Se(Ⅳ) treatments and controls both intra-and extra-cellular BSH concentration per biomass indicated that BSH contributes to Se(Ⅳ) reduction. Selenium-fortified rice was obtained by foliar spray of SeNPs synthesized by the strain ES2-45. To the best of our knowledge, DsbA and Aldo reductase were firstly verified for the role in Se(Ⅳ) reduction and Cr(Ⅵ)resistance. Importantly, it is a promising strategy that B. wiedmannii ES2-45 is served as an efficient bacterium for SeNP synthesis, selenium biofortification and heavy metal bioremediation.
基金Supported by the Top-level Talents Support Program of Yangzhou University“Lv Yang Jin Feng”Outstanding Doctor of Yangzhou,No.YZLYJFJH2023YXBS169Natural Science Foundation of Jiangsu Province,No.BK20240907.
文摘This letter critically comments on the article by Zheng et al investigating the role of aucubin in alleviating diabetic neuropathic pain(DNP).DNP arises from hyperglycaemia-induced nerve injury and microglial reprogramming toward aerobic glycolysis.Aldose reductase(also known as AKR1B1)redirects excess glucose flux through the polyol pathway,thus increasing oxidative stress and inflammation.Zheng et al show that aucubin,a plant iridoid glycoside,reverses streptozotocin-induced mechanical and thermal hypersensitivity and anxiety-like behaviour in mice.Mechanistically,aucubin restores microglial morphology,reduces glycolytic flux,enhances oxidative phosphorylation and lowers tumour necrosis factor-α,interleukin(IL)-1βand IL-6 levels in spinal tissue and cultures of the BV-2 microglial cell line.Network pharmacology and molecular docking analyses identify AKR1B1 as a key target,confirmed by the fact that short hairpin RNA knockdown of AKR1B1 eliminates the effects of aucubin.Contrary to the other studies,this study uniquely implicates the polyol pathway in microglial immunometabolism.
基金supported by the National Natural Science Foundation of China(Grant Nos.:U21A20407 and 81973467)Beijing Natural Science Foundation,China(Grant No.:7222276).
文摘Sennoside A(SA),a typical prodrug,exerts its laxative effect only after its transformation into rheinanthrone catalyzed by gut microbial hydrolases and reductases.Hydrolases have been identified,but reductases remain unknown.By linking a photoreactive group to the SA scaffold,we synthesized a photoaffinity probe to covalently label SA reductases and identified SA reductases using activity-based protein profiling(ABPP).From lysates of an active strain,Bifidobacterium pseudocatenulatum(B.pseudocatenulatum),397 proteins were enriched and subsequently identified using mass spectrometry(MS).Among these proteins,chromate reductase/nicotinamide adenine dinucleotide(NADH)phosphate(NADPH)-dependent flavin mononucleotide(FMN)reductase/oxygen-insensitive NADPH nitroreductase(nfrA)was identified as a potent SA reductase through further bioinformatic analysis and The Universal Protein Resource(UniProt)database screening.We also determined that recombinant nfrA could reduce SA.Our study contributes to further illuminating mechanisms of SA transformation to rheinanthrone and simultaneously offers an effective method to identify gut bacterial reductases.
基金Supported by National Natural Science Foundation of China,No.82001424.
文摘BACKGROUND Treatment of diabetic neuropathy is often limited by side effects.Aucubin,an iridoid glycoside derived from natural plants,exhibits notable anti-inflammatory and antioxidant properties.AIM To investigate the effects of aucubin on diabetic neuropathic pain(DNP)and glycolysis and inflammation in microglia.METHODS Streptozotocin(STZ)was used to establish a DNP animal model.Blood glucose levels and body weight of mice were measured following STZ administration.Paw withdrawal threshold was calculated for mechanical allodynia.Paw withdrawal latency was recorded for thermal hyperalgesia.The open field test and elevated plus maze was used to assess locomotor activity and anxiety-like behavior.Western blotting was utilized for analysis of protein expression.Immunofluorescence staining was measured for morphometric analysis of microglia.Glycolysis and ATP synthesis in BV-2 cell lines were detected by metabolic extracellular flux analysis.The SwissTargetPrediction and STRING databases were used for comprehensive screening to identify potential target proteins for aucubin.The molecular docking between the possible target proteins and aucubin was investigated using Auto Dock Tool.The BV-2 cell line was transfected with lentiviral AKR1B1-shRNA to further ascertain the function of AKR1B1 in the impact of aucubin on aerobic glycolysis and inflammation during high glucose stimulation.RESULTS Aucubin significantly improved pain and anxiety-like behavior in STZ-induced diabetic mice and restored microglial aerobic glycolysis and inflammation.Several public databases and molecular docking studies suggested that AKR1B1,MMP2 and MMP9 are involved in the effect of aucubin on DNP.Aucubin failed to restore aerobic glycolysis and inflammation in the context of AKR1B1 deficiency.CONCLUSION Aucubin has potential as a therapeutic agent for alleviating DNP by inhibiting expression of AKR1B1.
基金Supported by the National Natural Science Foundation of China(No.42276100)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Ulva prolifera,the primary causative species of green tide,has garnered significant attention due to its robust growth and reproductive capacity under high salt stress.However,there has been relatively little research on the regulation of high salt stress in this species.In this study,we observed that high salt stress suppressed the growth of U.prolifera and leading to the nitric oxide(NO)accumulation,along with increased gene expression levels and enzyme activity of S-nitrosoglutathione reductase(GSNOR).Treatment with GSNOR inhibitor resulted in elevated NO levels under high salt stress,accompanied by reduced activity of antioxidant enzymes and decreased glutathione(GSH)accumulation,making U.prolifera more sensitive to high salt stress.Conversely,NO scavenger treatment not only reduced NO levels,but also weakened the high salt stress tolerance of U.prolifera.Furthermore,using tandem mass tags(TMT)switch analysis and mass spectrometry,we observed a significant increase in S nitrosylated protein levels in U.prolifera under high salt stress,with further augmentation upon GSNOR inhibitor treatment.We also found high salt stress induced S-nitrosylation(SNO)of glutathione reductase(GR),which is negatively regulated by GSNOR,resulting in increased GR activity.Our results show that under short-term high salt stress,the elevated expression level of GSNOR avoided excessive accumulation of NO,and a certain amount of NO enhanced the activity of antioxidant enzymes through SNO modification,which improve the high salt stress tolerance of U.prolifera,whereas under long-term high salt stress,excessive NO was toxic to U.prolifera.
基金Financial support from the Science and Technology Innovation Program of Hunan Province(No.2022RC4044)。
文摘Selenium(Se),an essential micronutrient among the 15 vital elements required for human physiology,exerts its biological functions primarily through its incorporation into selenoproteins.To date,approximately 25 selenoproteins have been characterized in mammalian systems,including glutathione peroxidase(GPX),thioredoxin reductase(TrxR),and iodothyronine deiodinases(DIOs),all of which exhibit indispensable physiological functions.
文摘Chiral N-substituted amino amides and esters are ubiquitous scaffolds in pesticides and pharmaceutical chemicals,but their asymmetric synthesis remains challenging especially for those with multiple chiral centers.In this study,IR104 from Streptomyces aureocirculatus was identified from 157 wild-type imine reductases for the synthesis of(S)-2-((R)-2-oxo-4-propylpyrrolidin-1-yl)butanamide(antiepileptic drug Brivaracetam)via dynamic kinetic resolution reductive amination from ethyl 3-formylhexanoate and(S)-2-aminobutylamide with high diastereoselectivity.To further improve the catalytic efficiency of IR104,its mutant D191E/L195I/E253S/M258A(M3)was identified by saturation mutagenesis and iterative combinatorial mutagenesis,which exhibited a 102-fold increase in the catalytic efficiency relative to that of wild-type enzyme and high diastereoselectivity(98:2 d.r.).Crystal structural analysis and molecular dynamics simulations provided some insights into the molecular basis for the improved activity of the mutant enzyme.The imine reductase identified in this study could accept chiral amino amides/esters as amino donors for the dynamic kinetic resolution reductive amination of racemicα-substituted aldehydo-esters,expanding the substrate scope of imine reductases in the dynamic kinetic resolution-reductive amination.Finally,IR104-M3 was successfully used for the preparation of Brivaracetam at gram scale.Using this mutant,various N-substituted amino amides/esters with two chiral centers were also synthesized with up to 99:1 d.r.and 96%yields and subsequently converted intoγ-andδ-lactams,providing an efficient protocol for the synthesis of these important compounds via enzymatic dynamic kinetic resolution-reductive amination from simple building blocks.
