| A Mechanistic Study of Trichoderma reesei Cel7B Catalyzed Glycosidic Bond Cleavage | |
| Zhang, Yu; Yan, Shihai; Yao, Lishan | |
| 2013-07-25 | |
| 发表期刊 | JOURNAL OF PHYSICAL CHEMISTRY B
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| 卷号 | 117期号:29页码:8714-8722 |
| 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). ; 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). |
| 文章类型 | Article |
| 学科领域 | 仿真与模拟 |
| WOS标题词 | Science & Technology ; Physical Sciences |
| DOI | 10.1021/jp403999s |
| 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研究方向 | Chemistry |
| WOS类目 | Chemistry, Physical |
| WOS记录号 | WOS:000322505200008 |
| 引用统计 | |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://ir.qibebt.ac.cn/handle/337004/1639 |
| 专题 | 蛋白质设计研究组 |
| 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. |
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