...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >Alteration of Hydrogen Bonding in the Vicinity of Histidine 48 Disrupts Millisecond Motions in RNase A
【24h】

Alteration of Hydrogen Bonding in the Vicinity of Histidine 48 Disrupts Millisecond Motions in RNase A

机译：组氨酸48附近氢键的改变破坏了RNase A中的毫秒运动

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

The motion of amino acid residues on the millisecond (ms) time scale is involved in the tight regulation of catalytic function in numerous enzyme systems. Using a combination of mutational, enzymological, and relaxation-compensated ~(15)N Carr-Purcell-Meiboom-Gill (CPMG) methods, we have previously established the conformational significance of the distant His48 residue and the neighboring loop 1 in RNase A function. These studies suggested that RNase A relies on an intricate network of hydrogen bonding interactions involved in propagating functionally relevant, long-range ms motions to the catalytic site of the enzyme. To further investigate the dynamic importance of this H-bonding network, this study focuses on the individual replacement of Thr17 and Thr82 with alanine, effectively altering the key H-bonding interactions that connect loop 1 and His48 to the rest of the protein. ~(15)N CPMG dispersion studies, nuclear magnetic resonance (NMR) chemical shift analysis, and NMR line shape analysis of point mutants T17A and T82A demonstrate that the evolutionarily conserved single H-bond linking His48 to Thr82 is essential for propagating ms motions from His48 to the active site of RNase A on the time scale of catalytic turnover, whereas the T17A mutation increases the off rate and conformational exchange motions in loop 1. Accumulating evidence from our mutational studies indicates that residues experiencing conformational exchange in RNase A can be grouped into two separate clusters displaying distinct dynamical features, which appear to be independently affected by mutation. Overall, this study illuminates how tightly controlled and finely tuned ms motions are in RNase A, suggesting that designed modulation of protein motions may be possible.
机译：氨基酸残基在毫秒（ms）时标上的运动涉及许多酶系统中催化功能的严格调节。使用突变，酶学和松弛补偿〜（15）N Carr-Purcell-Meiboom-Gill（CPMG）方法的组合，我们以前已经确定了遥远的His48残基和RNase A功能中相邻环1的构象意义。 。这些研究表明，RNase A依赖于复杂的氢键相互作用网络，该功能涉及将功能相关的长距离ms运动传播到酶的催化位点。为了进一步研究此H键网络的动态重要性，本研究着重于用丙氨酸单独替代Thr17和Thr82，有效改变连接环1和His48与其余蛋白质的关键H键相互作用。 〜（15）N CPMG分散研究，核磁共振（NMR）化学位移分析和点突变体T17A和T82A的NMR线形分析表明，将His48与Thr82连接的进化上保守的单H键对于从中传播ms运动是必不可少的在催化转换的时间尺度上，His48到RNase A的活性位点，而T17A突变增加了环1中的关闭率和构象交换运动。从我们的突变研究中积累的证据表明，可以对在RNase A中经历构象交换的残基进行分组。分为两个独立的群集，这些群集显示出明显的动态特征，这些特征似乎受突变独立影响。总的来说，这项研究阐明了RNase A中ms运动的严格控制和微调，表明蛋白质运动的设计调节是可能的。

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