Although supramolecular transformations have been emerged as a potent strategy for transitioning between various topologies,post-modification induced topological transformations have never been explored in the context...Although supramolecular transformations have been emerged as a potent strategy for transitioning between various topologies,post-modification induced topological transformations have never been explored in the context of[2]catenane topologies.In this study,we present a novel supramolecular transformation between a Hopf link and a macrocycle,induced by the Diels–Alder click reaction.By strategically selecting the half-sandwich ruthenium binuclear fragment B as a rigid capping agent,we successfully integrated tetrazine moieties into the metalla[2]catenane structure.We demonstrated that the introduction of 2,5-norbornadiene(NBD)as an external stimulus allows for the transformation of the novel metalla[2]catenane,featuring reactive tetrazine sites,into the corresponding monomeric ring through postmodification for the first time.The synthetic results are corroborated by single-crystal X-ray diffraction analysis,ESI-TOF/MS,elemental analysis,and detailed solution-state NMR techniques.展开更多
Dual-atom catalysts(DACs) afford promising potential for oxygen reduction electrocatalysis due to their high atomic efficiency and high intrinsic activity.However,precise construction of dual-atom sites remains a chal...Dual-atom catalysts(DACs) afford promising potential for oxygen reduction electrocatalysis due to their high atomic efficiency and high intrinsic activity.However,precise construction of dual-atom sites remains a challenge.In this work,a post-modification strategy is proposed to precisely fabricate DACs for oxygen reduction electrocatalysis.Concretely,a secondary metal precursor is introduced to the primary single-atom sites to introduce direct metal-metal interaction,which ensures the formation of desired atom pair structure during the subsequent pyrolysis process and allows for successful construction of DACs.The as-prepared FeCo-NC DAC exhibits superior oxygen reduction electrocatalytic activity with a half-wave potential of 0,91 V vs.reversible hydrogen electrode.Zn-air batteries equipped with the FeCo-NC DAC demonstrate higher peak power density than those with the Pt/C benchmark.More importantly,this post-modification strategy is demonstrated universal to achieve a variety of dual-atom sites.This work presents an effective synthesis methodology for precise construction of catalytic materials and propels their applications in energy-related devices.展开更多
Utilizing metal-organic frameworks(MOFs) to design photocatalysts for CO_(2) reduction catalysts is an excellent idea but currently restricted by the relatively low activity. Enhancing CO_(2) affinity and tuning the o...Utilizing metal-organic frameworks(MOFs) to design photocatalysts for CO_(2) reduction catalysts is an excellent idea but currently restricted by the relatively low activity. Enhancing CO_(2) affinity and tuning the oxidation state of metal clusters in MOFs might be a solution to improve the catalytic performance.Herein, the Cl-bridge atoms in the metal clusters of a cobalt MOF were easily exchanged with OH-,which simultaneously oxidized a portion of Co(Ⅱ) to Co(Ⅲ) and resulted in a much enhanced photocatalytic activity for CO_(2) reduction. In contrast, the original framework does not exhibit such superior activity. Comprehensive characterizations on their physicochemical properties revealed that the introduction of hydroxyl group not only greatly increases the CO_(2) affinity but also alters the oxidation state of metal clusters, resulting in significantly improved photocatalytic activities for CO_(2) reduction. This work provides important insight into the design of efficient photocatalysts.展开更多
Selective methods for modulating RNA epigenetic modifications within living cells and organisms represent attractive techniques for investigating biological functions and medicinal application.In contrast to enzymatic...Selective methods for modulating RNA epigenetic modifications within living cells and organisms represent attractive techniques for investigating biological functions and medicinal application.In contrast to enzymatic methods,abiotic chemical modulation offers access to diverse new-to-natural functionalities.We herein report a visible light-assisted bioorthogonal reaction involving flavin mononucleotide,sodium azide,and blue light irradiation.In concert with previous chemical approaches mimicking the demodification pathway,our system functions as a powerful and selective post-modification enzyme that targets N^(6)-prenyl adenosine i^(6) A in RNA and enables the efficient construction of an artificial N^(6)-cyanomethyl adenosine(cnm^(6) A).Notably,most endogenous biomacromolecular functions,including other common RNA epigenetics,remained unaffected.Consequently,we have successfully modified i^(6) A in tRNA to cnm^(6) A in human cells and establish this system as a bona fide bioorthogonal reaction with potential applications in chemical biology and in-cell modulation.展开更多
During the catalytic process,the microenvironment and surface area of the catalyst will affect the catalytic performance.Hence,an assisted organic linker coated metal-organic framework(MOF)has been applied,to form Ni/...During the catalytic process,the microenvironment and surface area of the catalyst will affect the catalytic performance.Hence,an assisted organic linker coated metal-organic framework(MOF)has been applied,to form Ni/HNC(HNC represents hollow nanocage)for electrocatalytic CO_(2)reduction.Remarkably,Ni/HNC achieves superb activity with high Faradaic efficiency(FE)of 97.2%at 0.7 V vs.reversible hydrogen electrode(RHE)towards CO_(2)conversion to CO.In contrast to Ni/NPC(afforded from the naked MOF),the Ni/HNC displays higher FE and selectivity on CO rather than H_(2),owing to the large nanocage which extraordinarily facilitates CO_(2)enrichment and the active sites easily accessible.This work provides a general and feasible route to construct high-efficient electrochemical CO_(2)reduction reaction(EC-CO_(2)RR)catalysts via post-modified MOFs.展开更多
The issue of ＂headedness＂ is a product of Chomsky＇s （1988） notion of UG （Universal Grammar） that led to the development of a framework known as P＆P （Principles and Parameters） theory. It is this theory we ha...The issue of ＂headedness＂ is a product of Chomsky＇s （1988） notion of UG （Universal Grammar） that led to the development of a framework known as P＆P （Principles and Parameters） theory. It is this theory we have adopted for our analysis in this paper. The purpose of this paper is to examine the inconsistency in the value of Head Parameter with reference to the value of DP （determiner phrase） in Yorfib^i. As a native speaker of Yorfib~, the author has adopted an introspective method of data collection and used the intuitive knowledge of other native speakers of the language for necessary clarifications. Despite the fact that English and Yorfib~ are both head-initial, the structure of the NPs （noun phrases） in English shows that the head noun is always pre-modified, making the NP ＂head-final＂--a violation of the value of Head Parameter in the language. This necessitated the need for Abney＇s （1987） DP hypothesis; in which the determiner heads its own phrase, thereby making a NP in English head-initial. This solves the problem of Head Parameter in English. However, since nouns in Yor/lb^i are post-modified, adopting ＂DP-analysis＂ will automatically produce head-final--a violation of the value of Head Parameter in the language. Given the inconsistency in the specification of head-complement order among the noun phrases in English and Yorfib~, this paper proposes to set a parameter for SVO （Subject-Verb-Object） languages with pre-modification （like English） to adopt ＂DP-analysis＂, and those with post-modification （like Yorfib^t） to adopt ＂NP-analysis＂. This will ensure ＂head-initial＂ value for the two categories of SVO languages展开更多
Warkmycin(1),a type II polyketide with complex post-modifications,exhibits potent antitumor activity.Through genome mining and biosynthetic investigations,we identified 20 warkmycin derivatives,17 of which are new.In ...Warkmycin(1),a type II polyketide with complex post-modifications,exhibits potent antitumor activity.Through genome mining and biosynthetic investigations,we identified 20 warkmycin derivatives,17 of which are new.In this study,we have corrected the nomenclature of sugar A in the structure of warkmycin(1)toα-L-oleandrose.We disclose here the biosynthetic pathway of warkmycins with a special emphasis on the spatiotemporal order of post-tailoring steps.Four glycosyltransferases(War8,War7,War10,and War11)sequentially loaded four rare deoxysugar groups:α-L-oleandrose,β-D-olivose,β-D-olivomycose,andβ-D-amicetose.Additionally,the cytochrome P450 enzyme War9 catalyzesβ-hydroxylation,the acetyltransferase War21 performs sequentially dual O-acetylation,and the carbamoyltransferase War1 facilitatesα-L-oleandrose carbamoylation to generate the final product warkmycin(1).In vitro enzyme reaction results showed that War9,War21,and War1 all have good catalytic activity and substrate promiscuity,which are of great value for the modification of complex molecules.Structureactivity relationship(SAR)studies demonstrated the essentiality of these enzymatic modifications for bioactivity.Notably,the intermediate warkmycin Q(18)exhibited superior antitumor activity.This work not only deciphers the complex enzymatic machinery governing polyketide diversification but also provides novel lead compounds for antitumor drug development and enzymatic tools for the engineering of natural products.展开更多
Microporous organic network(MON)has emerged as efficient stationary phases for high-performance liquid chromatographic(HPLC)separation.Nevertheless,the inherent superhydrophobic networks made their applications limite...Microporous organic network(MON)has emerged as efficient stationary phases for high-performance liquid chromatographic(HPLC)separation.Nevertheless,the inherent superhydrophobic networks made their applications limited in the reversedphase(RP)mode.In this work,a novel amino acid L-cysteine(L-Cys)modified core-shelled microsphere MON@SiO_(2)-L-Cys was synthesized via the efficient thiol-yne“click”reaction for hydrophilic interaction chromatography/reversed-phase liquid chromatography(HILIC/RPLC)mixed-mode chromatographic separation.Baseline separation of various hydrophilic and hydrophobic compounds including aromatic ketones,phthalate esters,alkylbenzenes,amines,polycyclic aromatic hydrocarbons,phenols,nucleosides,nucleic acid bases,sulfonamides,water-soluble vitamins,cephalosporin antibiotics,and estrogens was realized on MON@SiO_(2)-L-Cys packed column based on the predesigned mixed-mode retention mechanisms.The MON@SiO_(2)-L-Cys packed column also exhibited higher selectivity compared to bare SiO_(2),MON@SiO_(2)without L-Cys,and C_(18)packed columns,revealing the synergistic interactions of MON's networks and the modified L-Cys molecules.This work provided a feasible way to construct a novel amphipathic MON-based stationary phase,broadened the application scope of MON for hydrophilic analytes,and uncovered the prospects of MON in mixed-mode HPLC.展开更多
Various materials have been developed for environmental remediation of mercury ion pollution.Among these materials,covalent organic frameworks(COFs)can efficiently adsorb Hg(II)fromwater.Herein,two thiol-modified COFs...Various materials have been developed for environmental remediation of mercury ion pollution.Among these materials,covalent organic frameworks(COFs)can efficiently adsorb Hg(II)fromwater.Herein,two thiol-modified COFs(COF-S-SH and COF-OH-SH)were prepared,through the reaction between 2,5-divinylterephthalaldehyde and 1,3,5-tris-(4-aminophenyl)benzene,followed by post-synthetic modification using bis(2-mercaptoethyl)sulfide and dithiothreitol,respectively.The modified COFs showed excellent Hg(II)adsorption abilities with maximum adsorption capacities of 586.3 and 535.5 mg g^(-1)for COF-S-SH and COF-OH-SH,respectively.The prepared materials showed excellent selective absorbability for Hg(II)against multiple cationic metals in water.Unexpectedly,the experimental data showed that both co-existing toxic anionic diclofenac sodium(DCF)and Hg(II)performed positive effect for capturing another pollutant by these two modified COFs.Thus,a synergistic adsorption mechanism between Hg(II)and DCF on COFs was proposed.Moreover,density functional theory calculations revealed that synergistic adsorption occurred between Hg(II)and DCF,which resulted in a significant reduction in the adsorption system's energy.This work highlights a new direction for application of COFs to simultaneous removal of heavy metals and co-existing organic pollutants from water.展开更多
Aldehyde groups were intentionally equipped on the cyanide-bridged[Fe_(2)Co_(2)]square molecules:{[(Tp*)Fe(CN)_(3)Co(bpy^(CHO))_(2)]_(2)-[PF_(6)]_(2)}·4MeOH(1,Tp*=hydrotris(3,5-dimethylpyrazol-1-yl)borate;bpy^(CH...Aldehyde groups were intentionally equipped on the cyanide-bridged[Fe_(2)Co_(2)]square molecules:{[(Tp*)Fe(CN)_(3)Co(bpy^(CHO))_(2)]_(2)-[PF_(6)]_(2)}·4MeOH(1,Tp*=hydrotris(3,5-dimethylpyrazol-1-yl)borate;bpy^(CHO)=4-formyl-4′-methyl-2,2′-bipyridine),thus providing chemical-active windows for post-modification towards desired functions.In this contribution,by taking advantage of efficient Schiff-base condensation between the aldehyde-substituted bipyridine derivative(bpyCHO)and alkyl diamines(H_(2)N-(CH_(2))_(n)NH_(2)),two discrete[Fe_(2)Co_(2)]compounds{[(Tp∗)Fe(CN)_(3)Co(bpy^(C=N(CH_(2))_(n)N=C)bpy)]2[PF_(6)]_(2)}⋅6DMF(2,n=5;3,n=7)were prepared,where the cyanide-bridged[Fe_(2)Co_(2)]square cores were encapsulated by the flexible alkyl chains.Variable-temperature single-crystal X-ray diffraction and magnetic studies revealed complete thermo(T_(1/2)=233 K(2)and 237 K(3))and photo-induced electron transfer event accompanying spin transition between the diamagnetic[Fe^(Ⅱ)_(LS2)Co^(Ⅲ)_(LS2)]state and the paramagnetic[Fe^(Ⅲ)_(LS2)Co^(Ⅱ)_(HS2)]state(LS,low spin;HS,high spin).In addition,the bidirectional switching between the two states was achieved with alternating laser irradiation at 808 and 532 nm at 10 K.展开更多
Comprehensive Summary,Post-modification of polymers offers a route to prepare functionalized polymers through efficient chemical reactions,and hydrosilylation is one of the most effective strategies.Silane-functionali...Comprehensive Summary,Post-modification of polymers offers a route to prepare functionalized polymers through efficient chemical reactions,and hydrosilylation is one of the most effective strategies.Silane-functionalized polymers have found a wide range of potential applications,such as adhesives,rubbers,and drug delivery agents.For decades,the hydrosilylation for the post-modification of polymers has typically used transition metals as catalysts.Metal-free hydrosilylation strategies that can avoid metal residues in polymers are largely lacking in this field.Herein,we report the photocatalytic metal-free radical hydrosilylation strategy for the post-modification of polymers bearing pendant vinyl groups using the organic photocatalyst and hydrogen atom transfer(HAT)catalyst under blue light irradiation.We used monofunctional silanes to functionalize polymers and the bis(silane)s as crosslinkers to prepare crosslinked polymers.展开更多
Adsorbent-assisted air water harvesting(AWH)may help alleviate the current global freshwater scarcity crisis.However,the weak sorption capacity of various adsorbents and the high energy required to release water are t...Adsorbent-assisted air water harvesting(AWH)may help alleviate the current global freshwater scarcity crisis.However,the weak sorption capacity of various adsorbents and the high energy required to release water are two long-standing problems.Herein,we propose a class of green and clean adsorbent,TpPa-1@LiCl composite,whose sorption capacity is greatly improved to 0.37 and 0.80 g g^(-1)under 30%and 90%relative humidity(RH),respectively,and which has excellent stability,showing only a slight decrease(0.79%)after 10 sorp-tion–desorption cycles(1400 min).This TpPa-1@LiCl composite can reach equilibrium within 2 h and undergo complete desorption in 30 min under air mass 1.5 G irradiation.A corresponding solar-driven AWH device can complete up to 4 sorption–desorption cycles per day,with each cycle capable of collecting 0.34 g g^(-1)water without additional energy input,which implies TpPa-1@LiCl composite has the potential for achieving sorption-assisted AWH with high efficiency and rapid cycling.展开更多
Ebola virus （EBOV） is the causative agent of a severe hemorrhagic fever disease associ- ated with high mortality rates in humans. This virus has five strains of which Zaire Ebola virus （ZEBOV） is the first and mos...Ebola virus （EBOV） is the causative agent of a severe hemorrhagic fever disease associ- ated with high mortality rates in humans. This virus has five strains of which Zaire Ebola virus （ZEBOV） is the first and most important strain. It can be transmitted through contact with contaminated surfaces and objects. The genome of EBOV codes one non- structural and seven structural proteins consisting of two forms of glycoprotein （GP）： soluble glycoprotein （sGP） and GP （spike）. In this paper, we attempted to characterize and predict physicochemical properties, B-cell epitopes, mutation sites, phosphorylation sites, glycosylation sites, and different protein structures of EBOV GP to provide com- prehensive data about changes of this GP during a 40-years course （1976-2015）. GP sequences were obtained from NCBI gene bank from 1976-2015. Expasy＇sProtParam, PROTSCALE, immuneepitope, Bepipred, BcePred, ABCpred, VaxiJen, DISPHOS, Net- Phos, and numerous programs were used to predict and analyze all sequences. More variety of mutations were found in 2015 sequences and mutations were related to huge changes in B-cell epitopes, phosphorylation and glycosylation sites. In addition, our results determined different sites of disulfide bonds and an important mutation related to IgE epitope as well as four potent B-cell epitopes （380-387, 318-338, 405-438 and 434-475）. In this study, we suggested the effect of mutations on GP properties, six posi- tions for disulfide bonds and four phosphorylation sites for protein kinase C enzyme. Selected sequences were shown different sites for O-link and N-link glycosyl^tion. A mutation that changed GP to an allergen protein and has a significant role in vaccine designing as well as four potent B-cell epitopes in GP protein were found.展开更多
基金the Shanxi Province Science Foundation for Youth(No.202203021212408)the Shanxi Normal University Quality Curriculum(No.2019YZKC-13)the 1331 Project of Shanxi Province。
文摘Although supramolecular transformations have been emerged as a potent strategy for transitioning between various topologies,post-modification induced topological transformations have never been explored in the context of[2]catenane topologies.In this study,we present a novel supramolecular transformation between a Hopf link and a macrocycle,induced by the Diels–Alder click reaction.By strategically selecting the half-sandwich ruthenium binuclear fragment B as a rigid capping agent,we successfully integrated tetrazine moieties into the metalla[2]catenane structure.We demonstrated that the introduction of 2,5-norbornadiene(NBD)as an external stimulus allows for the transformation of the novel metalla[2]catenane,featuring reactive tetrazine sites,into the corresponding monomeric ring through postmodification for the first time.The synthetic results are corroborated by single-crystal X-ray diffraction analysis,ESI-TOF/MS,elemental analysis,and detailed solution-state NMR techniques.
基金This work was supported by the National Natural Science Foundation of China(22279008 and 22109082)the Beijing Institute of Technology Research Fund Program for Young Scholarsthe Tsinghua University Initiative Scientific Research Program。
文摘Dual-atom catalysts(DACs) afford promising potential for oxygen reduction electrocatalysis due to their high atomic efficiency and high intrinsic activity.However,precise construction of dual-atom sites remains a challenge.In this work,a post-modification strategy is proposed to precisely fabricate DACs for oxygen reduction electrocatalysis.Concretely,a secondary metal precursor is introduced to the primary single-atom sites to introduce direct metal-metal interaction,which ensures the formation of desired atom pair structure during the subsequent pyrolysis process and allows for successful construction of DACs.The as-prepared FeCo-NC DAC exhibits superior oxygen reduction electrocatalytic activity with a half-wave potential of 0,91 V vs.reversible hydrogen electrode.Zn-air batteries equipped with the FeCo-NC DAC demonstrate higher peak power density than those with the Pt/C benchmark.More importantly,this post-modification strategy is demonstrated universal to achieve a variety of dual-atom sites.This work presents an effective synthesis methodology for precise construction of catalytic materials and propels their applications in energy-related devices.
基金financially supported by the National Key Research and Development Program of China(No.2018YFA0208600)the National Natural Science Foundation of China(No.22033008)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZZ103)。
文摘Utilizing metal-organic frameworks(MOFs) to design photocatalysts for CO_(2) reduction catalysts is an excellent idea but currently restricted by the relatively low activity. Enhancing CO_(2) affinity and tuning the oxidation state of metal clusters in MOFs might be a solution to improve the catalytic performance.Herein, the Cl-bridge atoms in the metal clusters of a cobalt MOF were easily exchanged with OH-,which simultaneously oxidized a portion of Co(Ⅱ) to Co(Ⅲ) and resulted in a much enhanced photocatalytic activity for CO_(2) reduction. In contrast, the original framework does not exhibit such superior activity. Comprehensive characterizations on their physicochemical properties revealed that the introduction of hydroxyl group not only greatly increases the CO_(2) affinity but also alters the oxidation state of metal clusters, resulting in significantly improved photocatalytic activities for CO_(2) reduction. This work provides important insight into the design of efficient photocatalysts.
基金supported by the National Natural Science Foundation of China(grant nos.22022704,21977097,and 22271291)Chinese Academy of Sciencessupported by the Postdoctoral Innovative Talents Support Program(grant no.BX20200337).
文摘Selective methods for modulating RNA epigenetic modifications within living cells and organisms represent attractive techniques for investigating biological functions and medicinal application.In contrast to enzymatic methods,abiotic chemical modulation offers access to diverse new-to-natural functionalities.We herein report a visible light-assisted bioorthogonal reaction involving flavin mononucleotide,sodium azide,and blue light irradiation.In concert with previous chemical approaches mimicking the demodification pathway,our system functions as a powerful and selective post-modification enzyme that targets N^(6)-prenyl adenosine i^(6) A in RNA and enables the efficient construction of an artificial N^(6)-cyanomethyl adenosine(cnm^(6) A).Notably,most endogenous biomacromolecular functions,including other common RNA epigenetics,remained unaffected.Consequently,we have successfully modified i^(6) A in tRNA to cnm^(6) A in human cells and establish this system as a bona fide bioorthogonal reaction with potential applications in chemical biology and in-cell modulation.
基金This work was funded by the National Natural Science Foundation of China(NSFC)(No.21401004)the Natural Science Foundation of Anhui Province(Nos.1508085QB36 and 2008085MB52)+2 种基金the Key Research and Development Projects of Anhui Province(No.2022a05020048)the Open Foundation of Anhui Laboratory of Molecule-based Materials(No.fzj19005)the National Creative Plan of Students(No.202110370044).
文摘During the catalytic process,the microenvironment and surface area of the catalyst will affect the catalytic performance.Hence,an assisted organic linker coated metal-organic framework(MOF)has been applied,to form Ni/HNC(HNC represents hollow nanocage)for electrocatalytic CO_(2)reduction.Remarkably,Ni/HNC achieves superb activity with high Faradaic efficiency(FE)of 97.2%at 0.7 V vs.reversible hydrogen electrode(RHE)towards CO_(2)conversion to CO.In contrast to Ni/NPC(afforded from the naked MOF),the Ni/HNC displays higher FE and selectivity on CO rather than H_(2),owing to the large nanocage which extraordinarily facilitates CO_(2)enrichment and the active sites easily accessible.This work provides a general and feasible route to construct high-efficient electrochemical CO_(2)reduction reaction(EC-CO_(2)RR)catalysts via post-modified MOFs.
文摘The issue of ＂headedness＂ is a product of Chomsky＇s （1988） notion of UG （Universal Grammar） that led to the development of a framework known as P＆P （Principles and Parameters） theory. It is this theory we have adopted for our analysis in this paper. The purpose of this paper is to examine the inconsistency in the value of Head Parameter with reference to the value of DP （determiner phrase） in Yorfib^i. As a native speaker of Yorfib~, the author has adopted an introspective method of data collection and used the intuitive knowledge of other native speakers of the language for necessary clarifications. Despite the fact that English and Yorfib~ are both head-initial, the structure of the NPs （noun phrases） in English shows that the head noun is always pre-modified, making the NP ＂head-final＂--a violation of the value of Head Parameter in the language. This necessitated the need for Abney＇s （1987） DP hypothesis; in which the determiner heads its own phrase, thereby making a NP in English head-initial. This solves the problem of Head Parameter in English. However, since nouns in Yor/lb^i are post-modified, adopting ＂DP-analysis＂ will automatically produce head-final--a violation of the value of Head Parameter in the language. Given the inconsistency in the specification of head-complement order among the noun phrases in English and Yorfib~, this paper proposes to set a parameter for SVO （Subject-Verb-Object） languages with pre-modification （like English） to adopt ＂DP-analysis＂, and those with post-modification （like Yorfib^t） to adopt ＂NP-analysis＂. This will ensure ＂head-initial＂ value for the two categories of SVO languages
基金supported by the National Natural Science Foundation of China(U23A20107,22037006,82022067)the Guangdong Basic and Applied Basic Research Foundation(2023B1515120053)+3 种基金the Local Innovation and Entrepreneurship Team Project of Guangdong(2019BT02Y262)the Key Research and Development Project(2023YFA0914200,2022YFC2804105)the Rising Star Foundation of the South China Sea Institute of Oceanology(NHXX2019SW0101)the Nansha District Science and Technology Plan Project(NSJL202102)。
文摘Warkmycin(1),a type II polyketide with complex post-modifications,exhibits potent antitumor activity.Through genome mining and biosynthetic investigations,we identified 20 warkmycin derivatives,17 of which are new.In this study,we have corrected the nomenclature of sugar A in the structure of warkmycin(1)toα-L-oleandrose.We disclose here the biosynthetic pathway of warkmycins with a special emphasis on the spatiotemporal order of post-tailoring steps.Four glycosyltransferases(War8,War7,War10,and War11)sequentially loaded four rare deoxysugar groups:α-L-oleandrose,β-D-olivose,β-D-olivomycose,andβ-D-amicetose.Additionally,the cytochrome P450 enzyme War9 catalyzesβ-hydroxylation,the acetyltransferase War21 performs sequentially dual O-acetylation,and the carbamoyltransferase War1 facilitatesα-L-oleandrose carbamoylation to generate the final product warkmycin(1).In vitro enzyme reaction results showed that War9,War21,and War1 all have good catalytic activity and substrate promiscuity,which are of great value for the modification of complex molecules.Structureactivity relationship(SAR)studies demonstrated the essentiality of these enzymatic modifications for bioactivity.Notably,the intermediate warkmycin Q(18)exhibited superior antitumor activity.This work not only deciphers the complex enzymatic machinery governing polyketide diversification but also provides novel lead compounds for antitumor drug development and enzymatic tools for the engineering of natural products.
基金supported by the National Natural Science Foundation of China(22174071 and 22206114)the Natural Science Foundation of Shandong Province(ZR2022YQ08 and ZR2022QB085)+4 种基金the Joint Innovation Team for Clinical&Basic Research(202401)the Open Fund of Key Laboratory of Smart Breeding(Co-construction by Ministry and Province)the Ministry of Agriculture and Rural Aff airs(2023-TJAUKLSBF-2311)the Shandong First Medical University(Shandong Academy of Medical Sciences)Young Scientists Foundation Cultivation Support Program(202201-071)the Academic Promotion Program of Shandong First Medical University(2019LJ003)。
文摘Microporous organic network(MON)has emerged as efficient stationary phases for high-performance liquid chromatographic(HPLC)separation.Nevertheless,the inherent superhydrophobic networks made their applications limited in the reversedphase(RP)mode.In this work,a novel amino acid L-cysteine(L-Cys)modified core-shelled microsphere MON@SiO_(2)-L-Cys was synthesized via the efficient thiol-yne“click”reaction for hydrophilic interaction chromatography/reversed-phase liquid chromatography(HILIC/RPLC)mixed-mode chromatographic separation.Baseline separation of various hydrophilic and hydrophobic compounds including aromatic ketones,phthalate esters,alkylbenzenes,amines,polycyclic aromatic hydrocarbons,phenols,nucleosides,nucleic acid bases,sulfonamides,water-soluble vitamins,cephalosporin antibiotics,and estrogens was realized on MON@SiO_(2)-L-Cys packed column based on the predesigned mixed-mode retention mechanisms.The MON@SiO_(2)-L-Cys packed column also exhibited higher selectivity compared to bare SiO_(2),MON@SiO_(2)without L-Cys,and C_(18)packed columns,revealing the synergistic interactions of MON's networks and the modified L-Cys molecules.This work provided a feasible way to construct a novel amphipathic MON-based stationary phase,broadened the application scope of MON for hydrophilic analytes,and uncovered the prospects of MON in mixed-mode HPLC.
基金supported by the International Cooperation Project of Qinghai Province(Grant No.2021-HZ-809)the Key Youth Foundation of Qinghai University(Grant No.2021-QGY-1).
文摘Various materials have been developed for environmental remediation of mercury ion pollution.Among these materials,covalent organic frameworks(COFs)can efficiently adsorb Hg(II)fromwater.Herein,two thiol-modified COFs(COF-S-SH and COF-OH-SH)were prepared,through the reaction between 2,5-divinylterephthalaldehyde and 1,3,5-tris-(4-aminophenyl)benzene,followed by post-synthetic modification using bis(2-mercaptoethyl)sulfide and dithiothreitol,respectively.The modified COFs showed excellent Hg(II)adsorption abilities with maximum adsorption capacities of 586.3 and 535.5 mg g^(-1)for COF-S-SH and COF-OH-SH,respectively.The prepared materials showed excellent selective absorbability for Hg(II)against multiple cationic metals in water.Unexpectedly,the experimental data showed that both co-existing toxic anionic diclofenac sodium(DCF)and Hg(II)performed positive effect for capturing another pollutant by these two modified COFs.Thus,a synergistic adsorption mechanism between Hg(II)and DCF on COFs was proposed.Moreover,density functional theory calculations revealed that synergistic adsorption occurred between Hg(II)and DCF,which resulted in a significant reduction in the adsorption system's energy.This work highlights a new direction for application of COFs to simultaneous removal of heavy metals and co-existing organic pollutants from water.
基金This work was supported by the National Natural Science Foundation of China(21671095,21901108),and start-up fund from SUSTech.We thank Dr.Bin Chen from Soochow University for UV-Vis-NIR measurements.
文摘Aldehyde groups were intentionally equipped on the cyanide-bridged[Fe_(2)Co_(2)]square molecules:{[(Tp*)Fe(CN)_(3)Co(bpy^(CHO))_(2)]_(2)-[PF_(6)]_(2)}·4MeOH(1,Tp*=hydrotris(3,5-dimethylpyrazol-1-yl)borate;bpy^(CHO)=4-formyl-4′-methyl-2,2′-bipyridine),thus providing chemical-active windows for post-modification towards desired functions.In this contribution,by taking advantage of efficient Schiff-base condensation between the aldehyde-substituted bipyridine derivative(bpyCHO)and alkyl diamines(H_(2)N-(CH_(2))_(n)NH_(2)),two discrete[Fe_(2)Co_(2)]compounds{[(Tp∗)Fe(CN)_(3)Co(bpy^(C=N(CH_(2))_(n)N=C)bpy)]2[PF_(6)]_(2)}⋅6DMF(2,n=5;3,n=7)were prepared,where the cyanide-bridged[Fe_(2)Co_(2)]square cores were encapsulated by the flexible alkyl chains.Variable-temperature single-crystal X-ray diffraction and magnetic studies revealed complete thermo(T_(1/2)=233 K(2)and 237 K(3))and photo-induced electron transfer event accompanying spin transition between the diamagnetic[Fe^(Ⅱ)_(LS2)Co^(Ⅲ)_(LS2)]state and the paramagnetic[Fe^(Ⅲ)_(LS2)Co^(Ⅱ)_(HS2)]state(LS,low spin;HS,high spin).In addition,the bidirectional switching between the two states was achieved with alternating laser irradiation at 808 and 532 nm at 10 K.
基金the support from the National Natural Science Foundation of China(22271057)the Natural Science Foundation of Shanghai(22ZR1406000)the State Key Laboratory of Molecular Engineering of Polymers,Department of Macromolecular Science,and Fudan University.Z.Huang is also supported by the Shanghai Municipal Human Resources and Social Security Bureau,China(Shanghai Post-doctoral Excellence Program,No.2022035).
文摘Comprehensive Summary,Post-modification of polymers offers a route to prepare functionalized polymers through efficient chemical reactions,and hydrosilylation is one of the most effective strategies.Silane-functionalized polymers have found a wide range of potential applications,such as adhesives,rubbers,and drug delivery agents.For decades,the hydrosilylation for the post-modification of polymers has typically used transition metals as catalysts.Metal-free hydrosilylation strategies that can avoid metal residues in polymers are largely lacking in this field.Herein,we report the photocatalytic metal-free radical hydrosilylation strategy for the post-modification of polymers bearing pendant vinyl groups using the organic photocatalyst and hydrogen atom transfer(HAT)catalyst under blue light irradiation.We used monofunctional silanes to functionalize polymers and the bis(silane)s as crosslinkers to prepare crosslinked polymers.
基金supported by the Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City(No.520LH053)the National Natural Science Foundation of China(12174298)+3 种基金the National Natural Science Foundation of Shenzhen City(No.JCYJ20210324135002007)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515010130)the Fundamental Research Funds for the Cornell University(No.2021Szvup104)the 111 Project(No.B18038).
文摘Adsorbent-assisted air water harvesting(AWH)may help alleviate the current global freshwater scarcity crisis.However,the weak sorption capacity of various adsorbents and the high energy required to release water are two long-standing problems.Herein,we propose a class of green and clean adsorbent,TpPa-1@LiCl composite,whose sorption capacity is greatly improved to 0.37 and 0.80 g g^(-1)under 30%and 90%relative humidity(RH),respectively,and which has excellent stability,showing only a slight decrease(0.79%)after 10 sorp-tion–desorption cycles(1400 min).This TpPa-1@LiCl composite can reach equilibrium within 2 h and undergo complete desorption in 30 min under air mass 1.5 G irradiation.A corresponding solar-driven AWH device can complete up to 4 sorption–desorption cycles per day,with each cycle capable of collecting 0.34 g g^(-1)water without additional energy input,which implies TpPa-1@LiCl composite has the potential for achieving sorption-assisted AWH with high efficiency and rapid cycling.
文摘Ebola virus （EBOV） is the causative agent of a severe hemorrhagic fever disease associ- ated with high mortality rates in humans. This virus has five strains of which Zaire Ebola virus （ZEBOV） is the first and most important strain. It can be transmitted through contact with contaminated surfaces and objects. The genome of EBOV codes one non- structural and seven structural proteins consisting of two forms of glycoprotein （GP）： soluble glycoprotein （sGP） and GP （spike）. In this paper, we attempted to characterize and predict physicochemical properties, B-cell epitopes, mutation sites, phosphorylation sites, glycosylation sites, and different protein structures of EBOV GP to provide com- prehensive data about changes of this GP during a 40-years course （1976-2015）. GP sequences were obtained from NCBI gene bank from 1976-2015. Expasy＇sProtParam, PROTSCALE, immuneepitope, Bepipred, BcePred, ABCpred, VaxiJen, DISPHOS, Net- Phos, and numerous programs were used to predict and analyze all sequences. More variety of mutations were found in 2015 sequences and mutations were related to huge changes in B-cell epitopes, phosphorylation and glycosylation sites. In addition, our results determined different sites of disulfide bonds and an important mutation related to IgE epitope as well as four potent B-cell epitopes （380-387, 318-338, 405-438 and 434-475）. In this study, we suggested the effect of mutations on GP properties, six posi- tions for disulfide bonds and four phosphorylation sites for protein kinase C enzyme. Selected sequences were shown different sites for O-link and N-link glycosyl^tion. A mutation that changed GP to an allergen protein and has a significant role in vaccine designing as well as four potent B-cell epitopes in GP protein were found.
