...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>International Journal of Molecular Sciences >Active Site Architecture and Reaction Mechanism Determination of Cold Adapted β- d -galactosidase from Arthrobacter sp. 32cB
【24h】

Active Site Architecture and Reaction Mechanism Determination of Cold Adapted β- d -galactosidase from Arthrobacter sp. 32cB

机译：关节杆菌中冷适应性β-d-半乳糖苷酶的活性位点结构和反应机理测定32立方英尺

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Arth βDG is a dimeric, cold-adapted β- d -galactosidase that exhibits high hydrolytic and transglycosylation activity. A series of crystal structures of its wild form, as well as its Arth βDG_E441Q mutein complexes with ligands were obtained in order to describe the mode of its action. The Arth βDG_E441Q mutein is an inactive form of the enzyme designed to enable observation of enzyme interaction with its substrate. The resulting three-dimensional structures of complexes: Arth βDG_E441Q/LACs and Arth βDG/IPTG (ligand bound in shallow mode) and structures of complexes Arth βDG_E441Q/LACd, Arth βDG/ONPG (ligands bound in deep mode), and galactose Arth βDG/GAL and their analysis enabled structural characterization of the hydrolysis reaction mechanism. Furthermore, comparative analysis with mesophilic analogs revealed the most striking differences in catalysis mechanisms. The key role in substrate transfer from shallow to deep binding mode involves rotation of the F581 side chain. It is worth noting that the 10-aa loop restricting access to the active site in mesophilic GH2 βDGs, in Arth βDG is moved outward. This facilitates access of substrate to active site. Such a permanent exposure of the entrance to the active site may be a key factor for improved turnover rate of the cold adapted enzyme and thus a structural feature related to its cold adaptation.
机译：ArthβDG是一种冷适应的二聚体β-d-半乳糖苷酶，具有很高的水解和转糖基化活性。为了描述其作用方式，获得了一系列野生形式的晶体结构，以及带有配体的ArthβDG_E441Q突变蛋白复合物。 ArthβDG_E441Q突变蛋白是酶的一种非活性形式，旨在观察酶与其底物的相互作用。生成的复合物的三维结构：ArthβDG_E441Q/ LACs和ArthβDG/ IPTG（以浅模式结合的配体）和复合物ArthβDG_E441Q/ LACd，ArthβDG/ ONPG（以深模式结合的配体）和半乳糖ArthβDG / GAL及其分析可实现水解反应机理的结构表征。此外，与嗜温类似物的比较分析揭示了催化机理上最显着的差异。底物从浅结合模式转移到深结合模式的关键作用涉及F581侧链的旋转。值得注意的是，限制了ArthβDG中嗜温GH2βDGs进入活性位点的10-aa环向外移动。这有利于底物接近活​​性位点。活性部位入口的这种永久暴露可能是提高冷适应酶的周转率的关键因素，因此是与其冷适应有关的结构特征。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号