4.2 Article

Importance of the Hydrogen Bonding Network Including Asp52 for Catalysis, as Revealed by Asn59 Mutant Hen Egg-white Lysozymes

期刊

JOURNAL OF BIOCHEMISTRY
卷 146, 期 5, 页码 651-657

出版社

OXFORD UNIV PRESS
DOI: 10.1093/jb/mvp110

关键词

catalytic activity; lysozyme; proteincarbohydrate interactions; protein engineering; X-ray crystallography

资金

  1. Ministry of Education, Culture, Sports, Science, and Technology of Japan

向作者/读者索取更多资源

In the catalysis of sugar hydrolysis by hen egg-white lysozyme, Asp52 is thought to stabilize the reaction intermediate. This residue is involved in the well-ordered hydrogen bonding network including Asn46, Asp48, Ser50 and Asn59 on the anti-parallel -sheet, designated as a platform, on which the substrate sugar sits. To reveal the role of this hydrogen bonding network in the hydrolysis, we characterized Asn59 mutants by biochemical and crystallographic studies. Surprisingly, the introduction of only a methylene group by the Asn59Gln mutation markedly reduced the bacteriolytic activity and abolished the hydrolytic activity towards the synthetic substrate, PNP-(GlcNAc)(5). A similar result was also obtained with the Asn59Asp mutant. The crystal structure of the Asn59Asp mutant in complex with the substrate analogue revealed that, as in the wild-type, the (GlcNAc)(3) was bound in the ABC subsites. The reduced activity would be caused by subtle changes in the side-chain orientations as well as the electrostatic characteristics of Asp59, resulting in the rearrangement of the hydrogen bonding network of the platform. These results suggest that the precise locations of these platform residues, maintained by the well-ordered hydrogen bonding network, are crucial for efficient hydrolysis.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.2
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据