Department of Chemistry and Department of Physics, University of Illinois Chicago

报告人简介：

Huan-Xiang Zhou received his Ph.D. from Drexel University in 1988 and did postdoctoral work at the National Institutes of Health. After faculty appointments at Hong Kong University of Science and Technology, Drexel University, and Florida State University, he moved in 2017 to the University of Illinois Chicago, where he is Professor of Chemistry and Physics and holds an LAS Endowed Chair in the Natural Sciences. He was elected a fellow of the American Association for the Advancement of Science and a fellow of the American Physical Society. His group does theoretical, computational, and experimental research on molecular and cellular biophysics. Current interests include phase equilibrium and material properties of biomolecular condensates; membrane association and binding kinetics of intrinsically disordered proteins; functional mechanisms of glutamate-receptor ion channels; and structures and aggregation pathways of amyloid-beta and other amyloidogenic proteins. He has published over 300 peer-reviewed papers and has an H-index of 82.

报告摘要：

My group combines computational and experimental approaches to address a range of problems in molecular and cellular biophysics. We have been intrigued by two mysteries. The first is the high cellular concentration of ATP. The classical roles of ATP, as energy currency for active processes and as substrate for phosphorylation, require only micromolar ATP, yet cells spend an exorbitant amount of energy to maintain ATP at millimolar concentrations. A partial answer may be revealed by our recent discovery that ATP drives the phase separation of intrinsically disordered proteins (IDPs). Our molecular dynamics (MD) simulations show that ATP bridges between IDPs by extensive interactions including salt bridges and cation-pi. We used optical tweezers to measure the material properties of ATP-IDP droplets and found extreme shear thinning during droplet fusion. A second mystery is how DNA achieves enormous compaction in the nucleus. In somatic cells, the roles of histones and other proteins in compacting DNA are becoming well characterized. However, in sperm cells, histones are replaced by protamine. Our single-molecule pulling experiments have revealed multiple modes of DNA compaction by protamine; the resulting structure can withstand forces (> 50 pN) that are strong enough to produce strand separation. Our MD simulations show that this hyper-stability is driven by hydrogen bonds and cation-pi interactions between arginine residues of protamine and nucleobases.

报告地点：中国科学院物理研究所M楼253会议室

邀请人：李明 研究员（mingli@iphy.ac.cn）