Catalysts (Basel, Switzerland)最新文献

Evaluation of 3,3′-Triazolyl Biisoquinoline N,N′-Dioxide Catalysts for Asymmetric Hydrosilylation of Hydrazones with Trichlorosilane 3,3 ' -三唑基生物异喹啉N,N ' -二氧化氮催化剂对三氯硅烷不对称腙氢硅化反应的评价

Catalysts (Basel, Switzerland) Pub Date : 2021-09-01 DOI: 10.3390/catal11091103

Shi-yu Sun, Chang Xu, J. Jarvis, Phillip Nader, Brandon Naumann, Abigail Soliven, R. Peverati, N. Takenaka

引用次数: 2

Immobilization of β-Galactosidases on the Lactobacillus Cell Surface Using the Peptidoglycan-Binding Motif LysM 利用肽聚糖结合基序LysM在乳杆菌细胞表面固定化β-半乳糖苷酶

Catalysts (Basel, Switzerland) Pub Date : 2019-05-01 DOI: 10.3390/catal9050443

Mai-Lan Pham, Anh-Minh Tran, Suwapat Kittibunchakul, Tien-Thanh Nguyen, G. Mathiesen, Thu-Ha Nguyen

{"title":"Immobilization of β-Galactosidases on the Lactobacillus Cell Surface Using the Peptidoglycan-Binding Motif LysM","authors":"Mai-Lan Pham, Anh-Minh Tran, Suwapat Kittibunchakul, Tien-Thanh Nguyen, G. Mathiesen, Thu-Ha Nguyen","doi":"10.3390/catal9050443","DOIUrl":"https://doi.org/10.3390/catal9050443","url":null,"abstract":"Lysin motif (LysM) domains are found in many bacterial peptidoglycan hydrolases. They can bind non-covalently to peptidoglycan and have been employed to display heterologous proteins on the bacterial cell surface. In this study, we aimed to use a single LysM domain derived from a putative extracellular transglycosylase Lp_3014 of Lactobacillus plantarum WCFS1 to display two different lactobacillal β-galactosidases, the heterodimeric LacLM-type from Lactobacillus reuteri and the homodimeric LacZ-type from Lactobacillus delbrueckii subsp. bulgaricus, on the cell surface of different Lactobacillus spp. The β-galactosidases were fused with the LysM domain and the fusion proteins, LysM-LacLMLreu and LysM-LacZLbul, were successfully expressed in Escherichia coli and subsequently displayed on the cell surface of L. plantarum WCFS1. β-Galactosidase activities obtained for L. plantarum displaying cells were 179 and 1153 U per g dry cell weight, or the amounts of active surface-anchored β-galactosidase were 0.99 and 4.61 mg per g dry cell weight for LysM-LacLMLreu and LysM-LacZLbul, respectively. LysM-LacZLbul was also displayed on the cell surface of other Lactobacillus spp. including L. delbrueckii subsp. bulgaricus, L. casei and L. helveticus, however L. plantarum is shown to be the best among Lactobacillus spp. tested for surface display of fusion LysM-LacZLbul, both with respect to the immobilization yield as well as the amount of active surface-anchored enzyme. The immobilized fusion LysM-β-galactosidases are catalytically efficient and can be reused for several repeated rounds of lactose conversion. This approach, with the β-galactosidases being displayed on the cell surface of non-genetically modified food-grade organisms, shows potential for applications of these immobilized enzymes in the synthesis of prebiotic galacto-oligosaccharides.","PeriodicalId":221236,"journal":{"name":"Catalysts (Basel, Switzerland)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115401244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

An MM and QM Study of Biomimetic Catalysis of Diels-Alder Reactions Using Cyclodextrins 环糊精仿生催化Diels-Alder反应的MM和QM研究

Catalysts (Basel, Switzerland) Pub Date : 2017-07-28 DOI: 10.1101/169565

Wei Chen, Lipeng Sun, Zhiye Tang, Chia‐en A. Chang

{"title":"An MM and QM Study of Biomimetic Catalysis of Diels-Alder Reactions Using Cyclodextrins","authors":"Wei Chen, Lipeng Sun, Zhiye Tang, Chia‐en A. Chang","doi":"10.1101/169565","DOIUrl":"https://doi.org/10.1101/169565","url":null,"abstract":"We performed computational research to investigate the mechanism by which cyclodextrins (CDs) catalyze Diels-Alder reactions between 9-anthracenemethanol and N-cyclohexylmaleimide. Hydrogen bonds (Hbonds) between N-cyclohexylmaleimide and the hydroxyl groups of cyclodextrins were suggested to play an important role in the catalysis.However, our free energy calculations and molecular dynamics simulations showed that these Hbonds are not stable, and quantum mechanics calculations suggested that the reaction is not promoted by these Hbonds. The binding of 9-anthracenemethanol and N-cyclohexylmaleimide to cyclodextrins was the key to the catalysis. Cyclodextrins act as a container to hold the two reactants in the cavity, pre-organizes them for the reactions, and thus reduces the entropy penalty to the activation free energy. Dimethyl-β-CD was a better catalyst for this specific reaction than β-CD because of its stronger van der Waals interaction with the pre-organized reactants and better performance in reducing the activation energy. This computational work sheds light on the mechanism of the catalytic reaction by cyclodextrins and introduces new perspectives of supramolecular catalysis.","PeriodicalId":221236,"journal":{"name":"Catalysts (Basel, Switzerland)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124753935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Investigation of Structural Dynamics of Enzymes and Protonation States of Substrates Using Computational Tools 利用计算工具研究酶的结构动力学和底物的质子化状态

Catalysts (Basel, Switzerland) Pub Date : 2016-05-31 DOI: 10.3390/catal6060082

Chia‐en A. Chang, Yu‐ming M. Huang, L. J. Mueller, Wanli You

{"title":"Investigation of Structural Dynamics of Enzymes and Protonation States of Substrates Using Computational Tools","authors":"Chia‐en A. Chang, Yu‐ming M. Huang, L. J. Mueller, Wanli You","doi":"10.3390/catal6060082","DOIUrl":"https://doi.org/10.3390/catal6060082","url":null,"abstract":"This review discusses the use of molecular modeling tools, together with existing experimental findings, to provide a complete atomic-level description of enzyme dynamics and function. We focus on functionally relevant conformational dynamics of enzymes and the protonation states of substrates. The conformational fluctuations of enzymes usually play a crucial role in substrate recognition and catalysis. Protein dynamics can be altered by a tiny change in a molecular system such as different protonation states of various intermediates or by a significant perturbation such as a ligand association. Here we review recent advances in applying atomistic molecular dynamics (MD) simulations to investigate allosteric and network regulation of tryptophan synthase (TRPS) and protonation states of its intermediates and catalysis. In addition, we review studies using quantum mechanics/molecular mechanics (QM/MM) methods to investigate the protonation states of catalytic residues of β-Ketoacyl ACP synthase I (KasA). We also discuss modeling of large-scale protein motions for HIV-1 protease with coarse-grained Brownian dynamics (BD) simulations.","PeriodicalId":221236,"journal":{"name":"Catalysts (Basel, Switzerland)","volume":"202 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121750421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9