报 告 人：George Lorimer（University Of Maryland）
报告时间：2015年5月29日（星期五）下午2：00
报告地点：嘉定园区学术活动中心一楼多功能厅
George LorimerAbstractSome 50 years ago Anfinsen showed that the folded, biologically active form of most proteins is its thermodynamically most stable state. This state can be reached by a spontaneous, exergonic folding reaction that can occur in the absence of cellular catalysts (enzymes), without the expenditure of cellular energy (ATP). But not all proteins do so under all conditions. Twenty-five years ago we demonstrated the existence of a group of indispensible proteins (the chaperonins GroEL and GroES) that, driven by the hydrolysis of ATP, enable these recalcitrant proteins to achieve their native states. The chaperonins are cellular machines, progressing through a series of distinct structural states that can be structurally described by crystallography and cryo-EMandkinetically and thermodynamically described by multiple spectroscopies. During the course of a chaperonin cycle, the unfolded substrate protein is captured by a vacant GroEL ring, transiently encapsulated in the central cavity and released, folded or not, after a few seconds. The yield of folded protein per cycle is typically just a few percent, necessitating multiple iterative cycles. Our extensive pre-steady state analyses, employing multiple spectroscopic probes, demonstrate that the chaperonins function as parallel-processing, iterative annealing machines.