A Mechanistic Study of Trichoderma reesei Cel7B Catalyzed Glycosidic Bond Cleavage

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	A Mechanistic Study of Trichoderma reesei Cel7B Catalyzed Glycosidic Bond Cleavage
	Zhang, Yu; Yan, Shihai; Yao, Lishan
刊名	JOURNAL OF PHYSICAL CHEMISTRY B
	2013-07-25
卷号	117 期号:29 页码:8714-8722
中文摘要	An ONIOM study is performed to illustrate the mechanism of Trichoderma reesei Cel7B catalyzed p-nitrophenyl lactoside hydrolysis. In both the glycosylation and deglycosylation steps, the reaction proceeds in a concerted way, meaning the nucleophilic attack and the glycosidic bond cleavage occur simultaneously. The glycosylation step is rate limiting with a barrier of 18.9 kcal/mol, comparable to the experimental value derived from the kcat measured in this work. The function of four residues R108, Y146, Y170, and D172, which form a hydrogen-bond network involving the substrate, is studied by conservative mutations. The mutants, including R108K, Y146F, Y170F, and D172N, decrease the enzyme activity by about 150−8000-fold. Molecular dynamics simulations show that the mutations disrupt the hydrogen-bond network, cause the substrate to deviate from active binding and hinder either the proton transfer from E201 to O4(+1) or the nucleophilic attack from E196 to C1(−1).
英文摘要	An ONIOM study is performed to illustrate the mechanism of Trichoderma reesei Cel7B catalyzed p-nitro-phenyl lactoside hydrolysis. In both the glycosylation and deglycosylation steps, the reaction proceeds in a concerted way, meaning the nucleophilic attack and the glycosidic bond cleavage occur simultaneously. The glycosylation step is rate limiting with a barrier of 18.9 kcal/mol, comparable to the experimental value derived from the k(cat) measured in this work. The function of four residues R108, Y146, Y170, and D172, which form a hydrogen-bond network involving the substrate, is studied by conservative mutations. The mutants, including R108K, Y146F, Y170F, and D172N, decrease the enzyme activity by about 150-8000-fold. Molecular dynamics simulations show that the mutations disrupt the hydrogen-bond network, cause the substrate to deviate from active binding and hinder either the proton transfer from E201 to O-4(+1) or the nucleophilic attack from E196 to C-1(-1).
学科主题	仿真与模拟
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Chemistry, Physical
研究领域[WOS]	Chemistry
关键词[WOS]	AROMATIC-CARBOHYDRATE INTERACTIONS ; GREEN FLUORESCENT PROTEIN ; CELLULOSE-BINDING DOMAINS ; CELLOBIOHYDROLASE-I ; CRYSTAL-STRUCTURES ; ENDOGLUCANASE-I ; PK(A) VALUES ; STEREOCHEMICAL COURSE ; EFFICIENT GENERATION ; PROCESSIVE CELLULASE
收录类别	SCI
语种	英语
WOS记录号	WOS:000322505200008
公开日期	2014-03-21
内容类型	期刊论文
源URL	[http://ir.qibebt.ac.cn:8080/handle/337004/1639]
专题	青岛生物能源与过程研究所_仿真模拟团队
作者单位	Chinese Acad Sci, Lab Biofuels, Qingdao Inst Bioenergy & Bioproc Technol, Qingdao 266061, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Yu,Yan, Shihai,Yao, Lishan. A Mechanistic Study of Trichoderma reesei Cel7B Catalyzed Glycosidic Bond Cleavage[J]. JOURNAL OF PHYSICAL CHEMISTRY B,2013,117(29):8714-8722.
APA	Zhang, Yu,Yan, Shihai,&Yao, Lishan.(2013).A Mechanistic Study of Trichoderma reesei Cel7B Catalyzed Glycosidic Bond Cleavage.JOURNAL OF PHYSICAL CHEMISTRY B,117(29),8714-8722.
MLA	Zhang, Yu,et al."A Mechanistic Study of Trichoderma reesei Cel7B Catalyzed Glycosidic Bond Cleavage".JOURNAL OF PHYSICAL CHEMISTRY B 117.29(2013):8714-8722.