报告题目：Protein Dynamics on Multiple Timescales Studied by Neutron Scattering

时间：5月17号（周二）上午10：00

地点：物理学院新楼多功能厅

报告人：储祥蔷

报告简介：Proteins undergo sophisticated changes in space and time, in order to keep the cells functioning. These motions are believed to ultimately govern the biological function and activities of the protein. Neutron scattering provide exceptional tools for studying the structures and dynamics of protein in real time at the molecular level. In our recent research, quasi-elastic neutron scattering (QENS) experiments were carried out to study the protein dynamics by using a “state-of-the-art” backscattering spectrometer at the world’s largest neutron source at Oak Ridge National Lab (ORNL). As a result, an exotic logarithmic decay in the relaxational dynamics of proteins is observed in the time range of 10ps to 1ns. This is the first experimental observation of logarithmic behavior in protein relaxation. Our most recent results [1] further indicate that under a pressure of 100 MPa, close to that of the native environment deep under the sea, IPPase displays much faster relaxation dynamics than a mesophilic model protein, hen egg white lysozyme (HEWL) at all measured temperatures, opposite to what we observed previously under ambient pressure [2]. This contradictory observation provides evidence that the protein energy landscape is distorted by high pressure, which is significantly different for hyperthermophilic (IPPase) and mesophilic (HEWL) proteins. We further derive from our observations a schematic denaturation phase diagram together with energy landscapes for the two very different proteins, which can be used as a general picture to understand the dynamical properties of thermophilic proteins under pressure.

In addition, using a direct time-of-flight Fermi chopper neutron spectrometer (SEQUOIA) at ORNL, we obtained a full map of the milli-eV phonon-like excitations in the fully deuterated protein [3]. The Q range of the observed excitations corresponds to the length scale of about 2.5 to 3 Å, which is close to the length scales of the secondary structures of proteins (4-5 Å) and reflects the collective intra-protein motions [4]. These observations and further investigation using neutron scattering can reveal important macromolecular dynamic behaviors that cannot be otherwise measured by other techniques.

报告人简介：

储祥蔷,美国韦恩州立大学物理与天文系助理教授，博士生导师。2002和2005年分别于北京大学物理学院获得学士和硕士学位。2010年于美国麻省理工学院核科学与工程系获得博士学位，毕业后在美国橡树岭国家实验室进行博士后研究工作。2012年8月起被美国韦恩州立大学聘为终身制助理教授。主要研究兴趣包括利用中子散射和X射线散射以及分子动力学模拟研究生物大分子的结构和动力学性质，以及生物分子和纳米材料的相互作用。迄今为止已在国际知名期刊发表SCI论文二十余篇，包括PNAS, Physical Review Letters, Physical Review E, Journal of Physical Chemistry Letters, Journal of Physical Chemistry B, Soft Matter等。论文被引用550余次，h-index 12；研究成果曾被多家媒体报道。曾在美国物理学会年会等多个国际会议做邀请报告。现任Nature出版社Scientific Reports编委，并担任Nature Communications, Journal of Physical Chemistry Letters, Chemical Physics, Biopolymers等期刊的审稿人。