• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Molecular Biology >Evolutionary constraints for dimer formation in prokaryotic Cu,Zn superoxide dismutase.
【24h】

Evolutionary constraints for dimer formation in prokaryotic Cu,Zn superoxide dismutase.

机译：在原核Cu，Zn超氧化物歧化酶中二聚体形成的进化限制。

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Prokaryotic Cu,Zn superoxide dismutases are characterized by a distinct quaternary structure, as compared to that of the homologous eukaryotic enzymes. Here we report a newly determined crystal structure of the dimeric Cu,Zn superoxide dismutase from Photobacterium leiognathi (crystallized in space group R32, refined at 2.5 A resolution, R-factor 0.19) and analyse it in comparison with that of the monomeric enzyme from Escherichia coli. The dimeric assembly, observed also in a previously studied monoclinic crystal form of P. leiognathi Cu,Zn superoxide dismutase, is based on a ring-shaped subunit contact region, defining a solvated interface cavity. Three clusters of neighbouring residues play a direct role in the stabilization of the quaternary assembly. The present analysis, extended to the amino acid sequences of the other 11 known prokaryotic Cu,Zn superoxide dismutases, shows that at least in five other prokaryotic enzymes the interface residue clusters are under strong evolutionary constraint, suggesting the attainment of a quaternary structure coincident with that of P. leiognathi Cu,Zn superoxide dismutase. Calculation of electrostatic fields for both the enzymes from E. coli and P. leiognathi shows that the monomeric/dimeric association behaviour displayed by prokaryotic Cu, Zn superoxide dismutases is related to the distribution of surface charged residues. Moreover, Brownian dynamics simulations reproduce closely the observed enzyme:substrate association rates, highlighting the role of the active site neighbouring residues in determining the dismutase catalytic properties. Copyright 1999 Academic Press.
机译：与同源真核酶相比，原核Cu，Zn超氧化物歧化酶的特征在于独特的四级结构。在这里，我们报告了新确定的来自Leiognathi细菌的二聚体Cu，Zn超氧化物歧化酶的晶体结构（在R32空间群中结晶，以2.5 A的分辨率精制，R因子0.19），并与来自大肠杆菌的单体酶进行了比较大肠杆菌。二聚体组装体，也可以在先前研究的P. leiognathi Cu，Zn超氧化物歧化酶的单斜晶体形式中观察到，其基于环状亚基接触区域，限定了溶剂化的界面腔。相邻残基的三个簇在稳定四级组装中起直接作用。目前的分析，扩展到其他11种已知的原核Cu，Zn超氧化物歧化酶的氨基酸序列，表明至少在其他5种原核酶中，界面残基簇处于强大的进化约束下，表明获得了与P. leiognathi Cu，Zn超氧化物歧化酶对大肠杆菌和莱奥毕赤酵母酶的静电场的计算表明，原核Cu，Zn超氧化物歧化酶显示的单体/二聚体缔合行为与表面带电残基的分布有关。此外，布朗动力学模拟紧密地再现了观察到的酶：底物缔合速率，突出了活性位点邻近残基在确定歧化酶催化特性中的作用。版权所有1999，学术出版社。

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