• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of magnetic resonance >Spin relaxation measurements of electrostatic bias in intermolecular exploration
【24h】

Spin relaxation measurements of electrostatic bias in intermolecular exploration

机译：分子间勘探中静电偏压的自旋弛豫测量

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

We utilize the paramagnetic contribution to proton spin-lattice relaxation rate constants induced by freely diffusing charged paramagnetic centers to investigate the effect of charge on the intermolecular exploration of a protein by the small molecule. The proton NMR spectrum provided 255 resolved resonances that report how the explorer molecule local concentration varies with position on the surface. The measurements integrate over local dielectric constant variations, and, in principle, provide an experimental characterization of the surface free energy sampling biases introduced by the charge distribution on the protein. The experimental results for ribonuclease A obtained using positive, neutral, and negatively charged small nitroxide radicals are qualitatively similar to those expected from electrostatic calculations. However, while systematic electrostatic trends are apparent, the three different combinations of the data sets do not yield internally consistent values for the electrostatic contribution to the intermolecular free energy. We attribute this failure to the weakness of the electrostatic sampling bias for charged nitroxides in water and local variations in effective translational diffusion constant at the water-protein interface, which enters the nuclear spin relaxation equations for the nitroxide-proton dipolar coupling. (c) 2005 Elsevier Inc. All rights reserved.
机译：我们利用顺磁对质子自旋晶格弛豫速率常数的顺磁贡献，该常数是由自由扩散带电顺磁中心引起的，以研究电荷对小分子蛋白质分子间探索的影响。质子NMR光谱提供了255个分辨的共振，这些共振报告了资源管理器分子的局部浓度如何随表面位置的变化而变化。这些测量积分了局部介电常数变化，并且原则上提供了由蛋白质上电荷分布引入的表面自由能采样偏差的实验表征。使用带正电荷，中性电荷和带负电荷的小氮氧自由基获得的核糖核酸酶A的实验结果在质量上与静电计算所预期的结果相似。但是，尽管系统的静电趋势是显而易见的，但数据集的三种不同组合并未产生内部的一致值，即静电对分子间自由能的贡献。我们将此失败归因于水中带电氮氧化物的静电采样偏压的弱点以及水-蛋白界面处有效平移扩散常数的局部变化，这为氮氧化物-质子偶极耦合输入了核自旋弛豫方程。 （c）2005 Elsevier Inc.保留所有权利。

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