The adsorption of pollutants can not only promote the direct surface reaction,but also modify the catalyst itself to improve its photoelectric characteristics,which is rarely studied for water treatment with inorganic...The adsorption of pollutants can not only promote the direct surface reaction,but also modify the catalyst itself to improve its photoelectric characteristics,which is rarely studied for water treatment with inorganic photocatalyst.A highly crystalline BiOBr(c-BiOBr)was synthesized by a two-step preparation process.Owing to the calcination,the highly crystalline enhanced the interface interaction between pollutant and c-BiOBr.The complex of organic pollutant and[Bi_(2)O_(2)]^(2+)could promote the active electron transfer from the adsorbed pollutant to c-BiOBr for the direct pollutant degradation by holes(h^(+)).Moreover,the pollutant adsorption actually modified c-BiOBr and promoted more unpaired electrons,which would coupling with the photoexcitation to promote generate more O_(2)^(•-).The molecular modification effect derived from pollutant adsorption significantly improved the removal of pollutants.This work strongly deepens the understanding of the molecularmodification effect from the pollutant adsorption and develops a novel and efficient approach for water treatment.展开更多
Alginate,an acidic polysaccharide,is formed byβ-D-mannuronate(M)andα-L-guluronate(G).As a type of polysaccharide lyase,alginate lyase can efficiently degrade alginate into alginate oligosaccharides,having potential ...Alginate,an acidic polysaccharide,is formed byβ-D-mannuronate(M)andα-L-guluronate(G).As a type of polysaccharide lyase,alginate lyase can efficiently degrade alginate into alginate oligosaccharides,having potential applications in the food,medicine,and agriculture fields.However,the application of alginate lyase has been limited due to its low catalytic efficiency and poor temperature stability.In recent years,various structural features of alginate lyase have been determined,resulting in modification strategies that can increase the applicability of alginate lyase,making it important to summarize and discuss the current evidence.In this review,we summarized the structural features and catalytic mechanisms of alginate lyase.Molecular modification strategies,such as rational design,directed evolution,conserved domain recombination,and non-catalytic domain truncation,are also described in detail.Lastly,the application of alginate lyase is discussed.This comprehensive summary can inform future applications of alginate lyases.展开更多
Functional saccharide is a general term that is often used to refer to the functional oligosaccharides,functional saccharide alcohols,and functional dietary fibers.These functional saccharides exhibit some health bene...Functional saccharide is a general term that is often used to refer to the functional oligosaccharides,functional saccharide alcohols,and functional dietary fibers.These functional saccharides exhibit some health benefiting effects,such as having low calorie,preventing dental caries,and regulating intestinal disorders.Functional saccharides are widely used in food,health products,and the healthcare fields.The preparation of functional saccharides is accomplished mainly through reactions involving transglycosylation,isomerization,or hydrolysis catalyzed by glycosyltransferases,saccharide isomerases,and glycohydrolases,respectively.However,the poor catalytic properties of natural enzymes and low fermentation yields have restricted the large-scale industrial production of functional saccharides.Therefore,molecular modification and efficient expression of key enzymes for functional-saccharide preparation are very important for promoting the low-cost large-scale production of functional saccharides.In this report,the recent advances in functional optimization and expression preparation of enzymes related to functional saccharides are reviewed.展开更多
Photocatalytic technology has attracted much attention in the fields of clean energy and environmental governance.However,how to design and develop highly efficient photocatalytic materials remains an urgent scientifi...Photocatalytic technology has attracted much attention in the fields of clean energy and environmental governance.However,how to design and develop highly efficient photocatalytic materials remains an urgent scientific problem to be solved.This study focuses on enhancing photocatalytic activity through microstructure modification.Among them,ToRed-4 showed the most prominent performance.Under the illumination condition of 420 nm,its value was 13506 lmol g^(-1) h^(-1),which was approximately 18 times that of CN550(bulk g-C_(3)N_(4))(719 lmol g^(-1) h^(-1)).By using DFT calculations,the photocatalytic performance was deeply analyzed,revealing the significant advantages of the ToRed series in key performance indicators and the underlying synergy mechanisms,including the reduction of the HOMO-LUMO energy gap,the efficient separation of electron holes,the expansion of the electronic transition range,the transformation of the electrostatic potential distribution,the increase in dipole moment,and the optimization of the Coulomb attractive energy.The research results of this study provide a key basis for opening up new avenues for the design and development of highly efficient photocatalytic materials and are expected to play an important role in related fields.展开更多
Retaining the ultrathin structure of two-dimensional materials is very important for stabilizing their catalytic performances.However,aggregation and restacking are unavoidable,to some extent,due to the van der Waals ...Retaining the ultrathin structure of two-dimensional materials is very important for stabilizing their catalytic performances.However,aggregation and restacking are unavoidable,to some extent,due to the van der Waals interlayer interaction of two-dimensional materials.Here,we address this challenge by preparing an origami accordion structure of ultrathin twodimensional graphitized carbon nitride(oa-C_(3)N_(4))with rich vacancies.This novel structured oa-C_(3)N_(4) shows exceptional photocatalytic activity for the CO_(2) reduction reaction,which is 8.1 times that of the pristine C_(3)N_(4).The unique structure not only prevents restacking but also increases light harvesting and the density of vacancy defects,which leads to modification of the electronic structure,regulation of the CO_(2) adsorption energy,and a decrease in the energy barrier of the carbon dioxide to carboxylic acid intermediate reaction.This study provides a new avenue for the development of stable highperformance two-dimensional catalytic materials.展开更多
Unspecific peroxygenases(UPOs, EC 1.11.2.1) is a kind of thioheme enzyme capable of catalyzing various oxidations of inert C–H bonds using H_(2)O_(2) as an oxygen donor without cofactors. However, the enhancement of ...Unspecific peroxygenases(UPOs, EC 1.11.2.1) is a kind of thioheme enzyme capable of catalyzing various oxidations of inert C–H bonds using H_(2)O_(2) as an oxygen donor without cofactors. However, the enhancement of the H_(2)O_(2) tolerance of UPOs is always challenging. In this study, the A161C mutant of r Dca UPO,which originates from Daldinia caldariorum, was found to be highly H_(2)O_(2)-resistant. Compared with the wild type, the mutant r Dca UPO-A161C showed a 10-h prolonged half-life and a 64% improved enzyme activity when incubated in 10 mmol/L H_(2)O_(2). The crystal structure analysis at 1.47 A showed that r Dca UPOA161C exhibited 10 α-helixes(cyan) and a series of ordered rings, forming a single asymmetric spherical structure. The two conserved domains near heme formed an active site with the catalytic PCP and EHD regions(Glu86, His87, Asp88 residues). The H_(2)O_(2) tolerance of r Dca UPO-A161C was preliminarily explored by comparing its structure with the wild type. Notably, r Dca UPO-A161C showed significantly higher catalytic efficiency than the wild type for the production of hydroxyl fatty acids. This study is anticipated to provide an insight into the structure-function relationship and expand potential applications of UPOs.展开更多
The studies on the human toxicity of nanoparticles（NPs） are far behind the rapid development of engineered functionalized NPs. Fullerene has been widely used as drug carrier skeleton due to its reported low risk. Ho...The studies on the human toxicity of nanoparticles（NPs） are far behind the rapid development of engineered functionalized NPs. Fullerene has been widely used as drug carrier skeleton due to its reported low risk. However, different from other kinds of NPs, fullerene-based NPs（C_（60） NPs） have been found to have an anticoagulation effect, although the potential target is still unknown. In the study, both experimental and computational methods were adopted to gain mechanistic insight into the modulation of thrombin activity by nine kinds of C_（60） NPs with diverse surface chemistry properties. In vitro enzyme activity assays showed that all tested surface-modified C_（60） NPs exhibited thrombin inhibition ability. Kinetic studies coupled with competitive testing using 3 known inhibitors indicated that six of the C_（60） NPs, of greater hydrophobicity and hydrogen bond（HB） donor acidity or acceptor basicity, acted as competitive inhibitors of thrombin by directly interacting with the active site of thrombin. A simple quantitative nanostructure-activity relationship model relating the surface substituent properties to the inhibition potential was then established for the six competitive inhibitors.Molecular docking analysis revealed that the intermolecular HB interactions were important for the specific binding of C_（60） NPs to the active site canyon, while the additional stability provided by the surface groups through van der Waals interaction also play a key role in the thrombin binding affinity of the NPs. Our results suggest that thrombin is a possible target of the surface-functionalized C_（60） NPs relevant to their anticoagulation effect.展开更多
Antibiotic resistance genes(ARGs)are emerging environmental contaminants,with vertical gene transfer(VGT)in Escherichia coli(E.coli)contributing significantly to their spread.In this study,we sought to predict amino a...Antibiotic resistance genes(ARGs)are emerging environmental contaminants,with vertical gene transfer(VGT)in Escherichia coli(E.coli)contributing significantly to their spread.In this study,we sought to predict amino acid mutations in the DNA gyrase subunit A protein of E.coli,simulating resistance scenarios and evaluating the binding efficacy of quinolones(QNs),based on molecular docking analyses.To optimize QNs,we designed a three-dimensional quantitative structure-activity relationship model,thereby enabling the design of 153 substitutes.By screening for environmental friendliness and functional stability,we identified PM-55 and PM-58 as pharmacodynamically stable alternatives,using which the inhibition of VGT was enhanced by 65.52%and 75.86%,respectively.Furthermore,drug synergy experiments revealed that when combined with colistin sulfate E,this promoted the binding affinity of PM-58 to mutant proteins by 77.71%,mediated by an intensification of hydrophobic interactions and shorter hydrogen bonds.In addition,a machine learning-based random forest regression model was used to identify key molecular descriptors influencing drug synergy and the inhibition of ARGs,thereby providing a framework for designing sustainable antibiotic alternatives.This dual approach,which combines molecular modifications with drug synergy,offers practical solutions for mitigating the environmental dissemination of ARGs and will contribute to a more effective inhibition of antimicrobial resistance.展开更多
D-Mannose is an attractive functional sugar that exhibits many physiological benefits on human health.The demand for low-calorie sugars and sweeteners in foods are increasingly available on the market.Some sugar isome...D-Mannose is an attractive functional sugar that exhibits many physiological benefits on human health.The demand for low-calorie sugars and sweeteners in foods are increasingly available on the market.Some sugar isomerases,such as D-lyxose isomerase(D-LIase),can achieve an isomerization reaction between D-mannose and D-fructose.However,the weak thermostability of D-LIase limits its efficient conversion from D-fructose to D-mannose.Nonetheless,few studies are available that have investigated the molecular modification of D-LIase to improve its thermal stability.In this study,computer-aided tools including FireProt,PROSS,and Consensus Finder were employed to jointly design D-LIase mutants with improved thermostability for the first time.Finally,the obtained five-point mutant M5(N21G/E78P/V58Y/C119Y/K170P)showed high thermal stability and cat-alytic activity.The half-life of M5 at 65◦C was 10.22 fold,and the catalytic efficiency towards 600 g/L of D-fructose was 2.6 times to that of the wild type enzyme,respectively.Molecular dynamics simulation and intramolecular forces analysis revealed a thermostability mechanism of highly rigidity conformation,newly formed hydrogen bonds andπ-cation interaction between and within protein domains,and redistributed surface electrostatic charges for the mutant M5.This research provided a promising D-LIase mutant for the industrial production of D-mannose from D-fructose.展开更多
Perovskite solar cells (PSCs) have achieved significant progress in the past decade and a certified power conversion efficiency (PCE) of 26.0% has been achieved.The widely used organic hole transport materials (HTMs) ...Perovskite solar cells (PSCs) have achieved significant progress in the past decade and a certified power conversion efficiency (PCE) of 26.0% has been achieved.The widely used organic hole transport materials (HTMs) in PSCs are typically sensitive to the moisture environment and continuous light exposure.In contrast,the inorganic HTMs benefiting from their outstanding merits,such as excellent environmental stability,are considered as alternatives and have attracted much attention in PSCs.In this review,we provide a comprehensive summary of the fundamental properties and recent progress of inorganic HTMs in n-i-p and p-i-n structured PSCs.Additionally,we emphasize the importance of inorganic HTMs in the development of highly efficient and stable PSCs.展开更多
3-ketosteroidΔ^(1)-dehydrogenases(Δ^(1)-KstDs)are FAD-dependent and substrate-inducing enzymes,which catalyze the intro-duction of double bonds between C1 and C2 atoms of the A ring of 3-ketosteroid substrates.They ...3-ketosteroidΔ^(1)-dehydrogenases(Δ^(1)-KstDs)are FAD-dependent and substrate-inducing enzymes,which catalyze the intro-duction of double bonds between C1 and C2 atoms of the A ring of 3-ketosteroid substrates.They are essential in the initial stages of the steroid core's breakdown.Additionally,Δ^(1)-KstDs are particularly intriguing for applications in pharmaceutical manufacturing,environmental bioremediation,and the etiology of infectious illnesses.A wide range of microorganisms,particularly bacteria from the phylum Actinobacteria,haveΔ^(1)-KstDs.Δ^(1)-KstDs can be classified into at least seven separate groups based on the sequence data in NCBI,and the enzymes in each group exhibit unique structural and catalytic proper-ties.Understanding these properties completely is crucial for utilizing and developingΔ^(1)-KstDs in metabolic engineering and enzyme engineering.This review describes and explains the biochemical and enzymatic characteristics ofΔ^(1)-KstDs based on a phylogenetic tree.To assist in the selection of highly active enzymes for engineering applications,the three-dimensional structures ofΔ^(1)-KstDs associated with enzyme mechanisms are stressed.The biotechnological application of microbialΔ^(1)-KstDs is also covered in this article,including genetic engineering based on metabolic strains and related genetic modification techniques for creating new productive industrial strains,the development and transformation of the heterologous expression system,the molecular modification and the optimization of catalytic conditions,and the use of microbial fermentation to increase product yield.Furthermore,we also highlight the recent development in the use of isolatedΔ^(1)-KstDs combined with a FAD cofactor regeneration system.We conclude by summarizing the concepts and techniques used in subsequent research and application development.All of these knowledge might serve as a guide for new mining and industrial applications inΔ^(1)-KstDs.展开更多
The fatty acid ester of catechins such as(epi)gallocatechin(EGC)occur naturally in green tea but reports on their enzymatic synthesis and antioxidant evaluation is scarce.In this study,EGC esters were prepared via a o...The fatty acid ester of catechins such as(epi)gallocatechin(EGC)occur naturally in green tea but reports on their enzymatic synthesis and antioxidant evaluation is scarce.In this study,EGC esters were prepared via a one-step enzymatic transesterification.The main O-acylation products were 8 EGC monoesters consisting of varying acyl groups ranging from 2 to 18 carbon atoms(acetate,butyrate,caproate,caprylate,caprate,laurate,myristate,and stearate).The dimyristate and distearate esters of EGC were also exemplified as minor production during EGC’s enzymatic esterification.LC-ToF and NMR HSQC were used to characterize the structures of purified EGC esters.Besides,the antioxidant activity of purified EGC esters were evaluated and systematically compared via several classical chemical(DPPH,ABTS,FRAP,Fe^(2+)chelation assays),food(β-carotene bleaching assay),and biological(LDL and DNA oxidation assays)methods/models.The lipophilicity of EGC derivatives increased upon O-acyl-ation and was found to positively correlate with the chain length of their acyl groups.The dual effect of acyl chain length on altering EGC monoesters’antioxidant efficacies also corresponded well with previous data of the fatty acid esters of quercetin,gallic acid,EGCG,and resveratrol.Finally,response surface design was used to optimize the reaction condition to achieve the ultimate reaction yield of EGC monolaurate in a laboratory scale.Overall,the study results support that the acylated EGCs can serve as functional/health-beneficial ingredients for use in lipid-based matrices of cosmetics,supplements,and nutraceuticals.The enzymatic synthesis with opti-mized reaction conditions may be utilized for further pilot-scale manufacturing of similar analogs of EGC monolaurate.展开更多
基金supported by National Natural Science Foundation of China (Nos.52100032,51838005)Shandong Province Postdoctoral Program for Innovative Talent Support Plan (No.SDBX2022003)the Introduced Innovative R&D Team Project under the“The Pearl River Talent Recruitment Program”of Guangdong Province (2019ZT08L387).
文摘The adsorption of pollutants can not only promote the direct surface reaction,but also modify the catalyst itself to improve its photoelectric characteristics,which is rarely studied for water treatment with inorganic photocatalyst.A highly crystalline BiOBr(c-BiOBr)was synthesized by a two-step preparation process.Owing to the calcination,the highly crystalline enhanced the interface interaction between pollutant and c-BiOBr.The complex of organic pollutant and[Bi_(2)O_(2)]^(2+)could promote the active electron transfer from the adsorbed pollutant to c-BiOBr for the direct pollutant degradation by holes(h^(+)).Moreover,the pollutant adsorption actually modified c-BiOBr and promoted more unpaired electrons,which would coupling with the photoexcitation to promote generate more O_(2)^(•-).The molecular modification effect derived from pollutant adsorption significantly improved the removal of pollutants.This work strongly deepens the understanding of the molecularmodification effect from the pollutant adsorption and develops a novel and efficient approach for water treatment.
基金supported by the National Natural Science Foundation of China(31601410)The Suqian City Science and Technology Project(L201906)the Postgraduate Research and Practice Innovation Program of Jiangsu Province(KYCX20_1103)。
文摘Alginate,an acidic polysaccharide,is formed byβ-D-mannuronate(M)andα-L-guluronate(G).As a type of polysaccharide lyase,alginate lyase can efficiently degrade alginate into alginate oligosaccharides,having potential applications in the food,medicine,and agriculture fields.However,the application of alginate lyase has been limited due to its low catalytic efficiency and poor temperature stability.In recent years,various structural features of alginate lyase have been determined,resulting in modification strategies that can increase the applicability of alginate lyase,making it important to summarize and discuss the current evidence.In this review,we summarized the structural features and catalytic mechanisms of alginate lyase.Molecular modification strategies,such as rational design,directed evolution,conserved domain recombination,and non-catalytic domain truncation,are also described in detail.Lastly,the application of alginate lyase is discussed.This comprehensive summary can inform future applications of alginate lyases.
文摘Functional saccharide is a general term that is often used to refer to the functional oligosaccharides,functional saccharide alcohols,and functional dietary fibers.These functional saccharides exhibit some health benefiting effects,such as having low calorie,preventing dental caries,and regulating intestinal disorders.Functional saccharides are widely used in food,health products,and the healthcare fields.The preparation of functional saccharides is accomplished mainly through reactions involving transglycosylation,isomerization,or hydrolysis catalyzed by glycosyltransferases,saccharide isomerases,and glycohydrolases,respectively.However,the poor catalytic properties of natural enzymes and low fermentation yields have restricted the large-scale industrial production of functional saccharides.Therefore,molecular modification and efficient expression of key enzymes for functional-saccharide preparation are very important for promoting the low-cost large-scale production of functional saccharides.In this report,the recent advances in functional optimization and expression preparation of enzymes related to functional saccharides are reviewed.
基金supported by the National Ten Thousand Talents Plan and the high-performance computing platform of Guizhou Universitythe Program of Introducing Talents to Chinese Universities(no.D20023)+1 种基金the Central Government Guides Local Science and Technology Development Fund Projects(Qiankehezhongyindi(2023)001)the Frontiers Science Centre for Asymmetric Synthesis and Medicinal Molecules,and the Department of Education,Guizhou Province[Qianjiaohe KY(2020)004].
文摘Photocatalytic technology has attracted much attention in the fields of clean energy and environmental governance.However,how to design and develop highly efficient photocatalytic materials remains an urgent scientific problem to be solved.This study focuses on enhancing photocatalytic activity through microstructure modification.Among them,ToRed-4 showed the most prominent performance.Under the illumination condition of 420 nm,its value was 13506 lmol g^(-1) h^(-1),which was approximately 18 times that of CN550(bulk g-C_(3)N_(4))(719 lmol g^(-1) h^(-1)).By using DFT calculations,the photocatalytic performance was deeply analyzed,revealing the significant advantages of the ToRed series in key performance indicators and the underlying synergy mechanisms,including the reduction of the HOMO-LUMO energy gap,the efficient separation of electron holes,the expansion of the electronic transition range,the transformation of the electrostatic potential distribution,the increase in dipole moment,and the optimization of the Coulomb attractive energy.The research results of this study provide a key basis for opening up new avenues for the design and development of highly efficient photocatalytic materials and are expected to play an important role in related fields.
基金Jilin Province Science and Technology Development Program,Grant/Award Number:20190201233JCProject for Self-innovation Capability Construction of Jilin Province Development and Reform Commission,Grant/Award Number:2021C026+3 种基金Program for JLU Science and Technology Innovative Research Team,Grant/Award Numbers:JLUSTIRT,2017TD-09National Natural Science Foundation of China,Grant/Award Numbers:12034002,51872116Natural Science Funds for Distinguished Young Scholar of Heilongjiang Province,Grant/Award Number:JC2018004Excellent Young Foundation of Harbin Normal University,Grant/Award Number:XKYQ201304。
文摘Retaining the ultrathin structure of two-dimensional materials is very important for stabilizing their catalytic performances.However,aggregation and restacking are unavoidable,to some extent,due to the van der Waals interlayer interaction of two-dimensional materials.Here,we address this challenge by preparing an origami accordion structure of ultrathin twodimensional graphitized carbon nitride(oa-C_(3)N_(4))with rich vacancies.This novel structured oa-C_(3)N_(4) shows exceptional photocatalytic activity for the CO_(2) reduction reaction,which is 8.1 times that of the pristine C_(3)N_(4).The unique structure not only prevents restacking but also increases light harvesting and the density of vacancy defects,which leads to modification of the electronic structure,regulation of the CO_(2) adsorption energy,and a decrease in the energy barrier of the carbon dioxide to carboxylic acid intermediate reaction.This study provides a new avenue for the development of stable highperformance two-dimensional catalytic materials.
基金supported by the National Natural Science Foundation of China (No.32001633)the Key Program of Natural Science Foundation of China (No.31930084)Guangzhou Science and technology planning project (No.202102020370)。
文摘Unspecific peroxygenases(UPOs, EC 1.11.2.1) is a kind of thioheme enzyme capable of catalyzing various oxidations of inert C–H bonds using H_(2)O_(2) as an oxygen donor without cofactors. However, the enhancement of the H_(2)O_(2) tolerance of UPOs is always challenging. In this study, the A161C mutant of r Dca UPO,which originates from Daldinia caldariorum, was found to be highly H_(2)O_(2)-resistant. Compared with the wild type, the mutant r Dca UPO-A161C showed a 10-h prolonged half-life and a 64% improved enzyme activity when incubated in 10 mmol/L H_(2)O_(2). The crystal structure analysis at 1.47 A showed that r Dca UPOA161C exhibited 10 α-helixes(cyan) and a series of ordered rings, forming a single asymmetric spherical structure. The two conserved domains near heme formed an active site with the catalytic PCP and EHD regions(Glu86, His87, Asp88 residues). The H_(2)O_(2) tolerance of r Dca UPO-A161C was preliminarily explored by comparing its structure with the wild type. Notably, r Dca UPO-A161C showed significantly higher catalytic efficiency than the wild type for the production of hydroxyl fatty acids. This study is anticipated to provide an insight into the structure-function relationship and expand potential applications of UPOs.
基金supported by Chinese Academy of Sciences(XDB14030501)the National Natural Science Foundation(21277164,21177146,21621064)
文摘The studies on the human toxicity of nanoparticles（NPs） are far behind the rapid development of engineered functionalized NPs. Fullerene has been widely used as drug carrier skeleton due to its reported low risk. However, different from other kinds of NPs, fullerene-based NPs（C_（60） NPs） have been found to have an anticoagulation effect, although the potential target is still unknown. In the study, both experimental and computational methods were adopted to gain mechanistic insight into the modulation of thrombin activity by nine kinds of C_（60） NPs with diverse surface chemistry properties. In vitro enzyme activity assays showed that all tested surface-modified C_（60） NPs exhibited thrombin inhibition ability. Kinetic studies coupled with competitive testing using 3 known inhibitors indicated that six of the C_（60） NPs, of greater hydrophobicity and hydrogen bond（HB） donor acidity or acceptor basicity, acted as competitive inhibitors of thrombin by directly interacting with the active site of thrombin. A simple quantitative nanostructure-activity relationship model relating the surface substituent properties to the inhibition potential was then established for the six competitive inhibitors.Molecular docking analysis revealed that the intermolecular HB interactions were important for the specific binding of C_（60） NPs to the active site canyon, while the additional stability provided by the surface groups through van der Waals interaction also play a key role in the thrombin binding affinity of the NPs. Our results suggest that thrombin is a possible target of the surface-functionalized C_（60） NPs relevant to their anticoagulation effect.
文摘Antibiotic resistance genes(ARGs)are emerging environmental contaminants,with vertical gene transfer(VGT)in Escherichia coli(E.coli)contributing significantly to their spread.In this study,we sought to predict amino acid mutations in the DNA gyrase subunit A protein of E.coli,simulating resistance scenarios and evaluating the binding efficacy of quinolones(QNs),based on molecular docking analyses.To optimize QNs,we designed a three-dimensional quantitative structure-activity relationship model,thereby enabling the design of 153 substitutes.By screening for environmental friendliness and functional stability,we identified PM-55 and PM-58 as pharmacodynamically stable alternatives,using which the inhibition of VGT was enhanced by 65.52%and 75.86%,respectively.Furthermore,drug synergy experiments revealed that when combined with colistin sulfate E,this promoted the binding affinity of PM-58 to mutant proteins by 77.71%,mediated by an intensification of hydrophobic interactions and shorter hydrogen bonds.In addition,a machine learning-based random forest regression model was used to identify key molecular descriptors influencing drug synergy and the inhibition of ARGs,thereby providing a framework for designing sustainable antibiotic alternatives.This dual approach,which combines molecular modifications with drug synergy,offers practical solutions for mitigating the environmental dissemination of ARGs and will contribute to a more effective inhibition of antimicrobial resistance.
基金supported by the National Natural Science Foundation of China(32201963)Scientific Research Foundation of Hunan Provincial Education Department(22C0137).
文摘D-Mannose is an attractive functional sugar that exhibits many physiological benefits on human health.The demand for low-calorie sugars and sweeteners in foods are increasingly available on the market.Some sugar isomerases,such as D-lyxose isomerase(D-LIase),can achieve an isomerization reaction between D-mannose and D-fructose.However,the weak thermostability of D-LIase limits its efficient conversion from D-fructose to D-mannose.Nonetheless,few studies are available that have investigated the molecular modification of D-LIase to improve its thermal stability.In this study,computer-aided tools including FireProt,PROSS,and Consensus Finder were employed to jointly design D-LIase mutants with improved thermostability for the first time.Finally,the obtained five-point mutant M5(N21G/E78P/V58Y/C119Y/K170P)showed high thermal stability and cat-alytic activity.The half-life of M5 at 65◦C was 10.22 fold,and the catalytic efficiency towards 600 g/L of D-fructose was 2.6 times to that of the wild type enzyme,respectively.Molecular dynamics simulation and intramolecular forces analysis revealed a thermostability mechanism of highly rigidity conformation,newly formed hydrogen bonds andπ-cation interaction between and within protein domains,and redistributed surface electrostatic charges for the mutant M5.This research provided a promising D-LIase mutant for the industrial production of D-mannose from D-fructose.
基金the financial support from the National Natural Science Foundation of China(Grants No.52273182)the National Key Research and Development Program of China(Grant No.2019YFA0705900).
文摘Perovskite solar cells (PSCs) have achieved significant progress in the past decade and a certified power conversion efficiency (PCE) of 26.0% has been achieved.The widely used organic hole transport materials (HTMs) in PSCs are typically sensitive to the moisture environment and continuous light exposure.In contrast,the inorganic HTMs benefiting from their outstanding merits,such as excellent environmental stability,are considered as alternatives and have attracted much attention in PSCs.In this review,we provide a comprehensive summary of the fundamental properties and recent progress of inorganic HTMs in n-i-p and p-i-n structured PSCs.Additionally,we emphasize the importance of inorganic HTMs in the development of highly efficient and stable PSCs.
基金supported by the national key research and development program of China(2019YFA0905300).
文摘3-ketosteroidΔ^(1)-dehydrogenases(Δ^(1)-KstDs)are FAD-dependent and substrate-inducing enzymes,which catalyze the intro-duction of double bonds between C1 and C2 atoms of the A ring of 3-ketosteroid substrates.They are essential in the initial stages of the steroid core's breakdown.Additionally,Δ^(1)-KstDs are particularly intriguing for applications in pharmaceutical manufacturing,environmental bioremediation,and the etiology of infectious illnesses.A wide range of microorganisms,particularly bacteria from the phylum Actinobacteria,haveΔ^(1)-KstDs.Δ^(1)-KstDs can be classified into at least seven separate groups based on the sequence data in NCBI,and the enzymes in each group exhibit unique structural and catalytic proper-ties.Understanding these properties completely is crucial for utilizing and developingΔ^(1)-KstDs in metabolic engineering and enzyme engineering.This review describes and explains the biochemical and enzymatic characteristics ofΔ^(1)-KstDs based on a phylogenetic tree.To assist in the selection of highly active enzymes for engineering applications,the three-dimensional structures ofΔ^(1)-KstDs associated with enzyme mechanisms are stressed.The biotechnological application of microbialΔ^(1)-KstDs is also covered in this article,including genetic engineering based on metabolic strains and related genetic modification techniques for creating new productive industrial strains,the development and transformation of the heterologous expression system,the molecular modification and the optimization of catalytic conditions,and the use of microbial fermentation to increase product yield.Furthermore,we also highlight the recent development in the use of isolatedΔ^(1)-KstDs combined with a FAD cofactor regeneration system.We conclude by summarizing the concepts and techniques used in subsequent research and application development.All of these knowledge might serve as a guide for new mining and industrial applications inΔ^(1)-KstDs.
基金Natural Sciences and Engineering Research Council(NSERC)of Canada and Mitacs-Canada,for financial supportscholarship support from China Schol-arship Council(CSC).
文摘The fatty acid ester of catechins such as(epi)gallocatechin(EGC)occur naturally in green tea but reports on their enzymatic synthesis and antioxidant evaluation is scarce.In this study,EGC esters were prepared via a one-step enzymatic transesterification.The main O-acylation products were 8 EGC monoesters consisting of varying acyl groups ranging from 2 to 18 carbon atoms(acetate,butyrate,caproate,caprylate,caprate,laurate,myristate,and stearate).The dimyristate and distearate esters of EGC were also exemplified as minor production during EGC’s enzymatic esterification.LC-ToF and NMR HSQC were used to characterize the structures of purified EGC esters.Besides,the antioxidant activity of purified EGC esters were evaluated and systematically compared via several classical chemical(DPPH,ABTS,FRAP,Fe^(2+)chelation assays),food(β-carotene bleaching assay),and biological(LDL and DNA oxidation assays)methods/models.The lipophilicity of EGC derivatives increased upon O-acyl-ation and was found to positively correlate with the chain length of their acyl groups.The dual effect of acyl chain length on altering EGC monoesters’antioxidant efficacies also corresponded well with previous data of the fatty acid esters of quercetin,gallic acid,EGCG,and resveratrol.Finally,response surface design was used to optimize the reaction condition to achieve the ultimate reaction yield of EGC monolaurate in a laboratory scale.Overall,the study results support that the acylated EGCs can serve as functional/health-beneficial ingredients for use in lipid-based matrices of cosmetics,supplements,and nutraceuticals.The enzymatic synthesis with opti-mized reaction conditions may be utilized for further pilot-scale manufacturing of similar analogs of EGC monolaurate.
