...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Acta crystallographica.Section D. Biological crystallography >Structure of the wild-type TEM-1 beta-lactamase at 1.55 angstrom and the mutant enzyme Ser70Ala at 2.1 angstrom suggest the mode of noncovalent catalysis for the mutant enzyme
【24h】

Structure of the wild-type TEM-1 beta-lactamase at 1.55 angstrom and the mutant enzyme Ser70Ala at 2.1 angstrom suggest the mode of noncovalent catalysis for the mutant enzyme

机译：野生型结构TEM-1 beta-lactamase1.55埃和突变酶Ser70Ala2.1埃建议共价的方式突变酶的催化

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

One of the best-studied examples of a class A beta-lactamase is Escherichia coli TEM-1 beta-lactamase. In this class of enzymes, the active-site serine residue takes on the role of a nucleophile and carries out beta-lactam hydrolysis. Here, the structures of the wild-type and the S70G enzyme determined to 1.55 and 2.1 angstrom, respectively, are presented. In contrast to the previously reported 1.8 degrees structure, the active site of the wild-type enzyme ( 1.55 angstrom) structure does not contain sulfate and Ser70 appears to be in the deprotonated form. The X-ray crystal structure of the S70G mutant has an altered Ser130 side-chain conformation that influences the positions of water molecules in the active site. This change allows an additional water molecule to be positioned similarly to the serine hydroxyl in the wild-type enzyme. The structure of the mutant enzyme suggests that this water molecule can assume the role of an active-site nucleophile and carry out noncovalent catalysis. The drop in activity in the mutant enzyme is comparable to the drop observed in an analogous mutation of the nucleophilic serine in alkaline phosphatase, suggesting common chemical principles in the utilization of nucleophilic serine in the active site of different enzymes.
机译：研究类的例子之一大肠杆菌TEM-1 beta-lactamasebeta-lactamase。活性部位丝氨酸残基的角色亲核试剂和执行beta-lactam水解。和S70G酶决心1.55和2.1埃,分别。与之前报道的1.8度结构,野生型的活性部位没有酶(1.55埃)结构含有硫酸和Ser70似乎deprotonated形式。S70G突变Ser130侧链的改变构象影响的位置水分子的活性部位。允许一个额外的水分子定位类似于丝氨酸的羟基野生型酶。酶表明这水分子假设一个活性部位的亲核试剂的作用,进行共价催化。与突变酶的活动在一个类似的突变的下降亲核丝氨酸在碱性磷酸酶,常见的化学原理利用亲核丝氨酸的活跃网站不同的酶。

著录项

相似文献

  • 外文文献
  • 中文文献
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