名师大讲堂（七十八）预告

报告题目：Dynamics and mechanism of ultrafast water–protein interactions
报告人：仲冬平（美国俄亥俄州立大学教授）
时间：2016年11月28日10：00
地点：工3-208
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嘉宾简介：
   仲冬平教授是加州理工学院博士（师从1999年诺贝尔化学奖得主Ahmed Hassan Zewail），美国俄亥俄州州立大学物理系终身正教授。1999年，仲教授从加州理工学院博士毕业并成为获得“加州理工学院最佳博士生奖”的首位中国留学生；2005年，仲冬平获得美国科技大奖——全美 Parkward Foundation奖，该奖项每年只有16个人获得。2009年，仲冬平获得年度华人物理学会“杰出青年研究奖”。2009年当选美国物理学会会士（APS Fellow）。2013获得美国古根海姆基金会（John Simon Guggenheim Memorial Foundation）科学和艺术年度大奖。

内容简介：
   Protein hydration is essential to its structure, dynamics, and function, but water–protein interactions have not been directly observed in real time at physiological temperature to our awareness. By using a tryptophan scan with femtosecond spectroscopy, we simultaneously measured the hydration water dynamics and protein side-chain motions with temperature dependence. We observed the heterogeneous hydration dynamics around the global protein surface with two types of coupled motions, collective water/side-chain reorientation in a few picoseconds and cooperative water/side-chain restructuring in tens of picoseconds. The ultrafast dynamics in hundreds of femtoseconds is from the outer-layer, bulk-type mobile water molecules in the hydration shell. We also found that the hydration water dynamics are always faster than protein side-chain relaxations but with the same energy barriers, indicating hydration shell fluctuations driving protein side-chain motions on the picosecond time scales and thus elucidating their ultimate relationship.