• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >A novel approach towards studying functional enzyme dynamics using kinetic isotope effects and ultrafast vibrational spectroscopy.
【24h】

A novel approach towards studying functional enzyme dynamics using kinetic isotope effects and ultrafast vibrational spectroscopy.

机译：一种利用动力学同位素效应和超快振动光谱研究功能酶动力学的新颖方法。

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

This thesis presents preliminary work done in an effort to link enzyme kinetics and dynamics on femtosecond-picosecond timescale. Formate dehydrogenase, which catalyzes hydride transfer reaction, is selected as the model system for these studies. Kinetic isotope effects and three-pulse echo peak shift spectroscopy were the techniques employed to study the kinetics and dynamics respectively. The work done provides evidence in support of the Marcus-like model, which is presently well accepted amongst enzymologists. These studies provide information about the molecular fluctuations that prevail during an enzyme catalyzed hydrogen transfer reaction. The photon echo results for the ternary complexes show a lack of static contribution in the frequency-frequency correlation function and the intrinsic kinetic isotope effects exhibit no temperature dependence. These results suggest that, once the enzyme is near the transition state for the hydride transfer step, the structure around the active site is very well organized with the precise arrangement of the active site residues involved in the atom transfer. This optimized structure imposes severe constrains on the active site, making it rigid (motions on nanosecond time scale or slower, 0.03 cm-1, are not sensed by the chromophore). As a result, near the transition state only low amplitude, fast fluctuations are observed that sample all the conformations within a few picoseconds and no slow dynamics are observed. The photon echo results of the binary complex suggest that moving away from the transition state relaxes the constrains on the active site structure, and slower motions that are required to bring the system to the transition state become apparent. This novel approach of studying the kinetics and dynamics simultaneously corroborates the hypothesis made by the Marcus-like model and lays ground for future work, where dynamically altered mutants can be tested using this approach.
机译：本文提出了初步的工作，旨在将飞秒-皮秒时间尺度上的酶动力学和动力学联系起来。选择催化氢化物转移反应的甲酸酯脱氢酶作为这些研究的模型系统。动力学同位素效应和三脉冲回波峰移谱是分别研究动力学和动力学的技术。所做的工作为支持类似Marcus的模型提供了证据，该模型目前已被酶学家广泛接受。这些研究提供了有关在酶催化的氢转移反应中普遍存在的分子波动的信息。三元络合物的光子回波结果表明在频率-频率相关函数中缺乏静态贡献，固有的动力学同位素效应没有温度依赖性。这些结果表明，一旦酶接近氢化物转移步骤的过渡态，活性位点周围的结构就可以很好地组织起来，并且原子转移中所涉及的活性位点残基可以精确排列。这种优化的结构在活动位点上施加了严格的约束，使其变得僵硬（发色团无法感知到纳秒级或更小（<0.03 cm-1）的运动）。结果，在过渡状态附近仅观察到低振幅，快速波动，该波动在几皮秒内采样了所有构象，并且未观察到缓慢的动力学。二元复合物的光子回波结果表明，远离过渡态的移动会放松对活性位点结构的约束，并且使系统进入过渡态所需的较慢运动变得明显。这种研究动力学和动力学的新颖方法同时证实了类似Marcus的模型所作的假设，并为将来的工作奠定了基础，在那里可以使用这种方法测试动态变化的突变体。

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