报告题目: Induced-fit of the peptidyl-transferase center of the ribosome and conformational freedom of the esterified amino acids

报告人: Jean Lehmann Ph.D. Institute for Integrative Biology of the Cell, Université Paris-Sud, France.

主持人: 袁崇刚 教授

报告时间: 2016-4-20  13:30-15:00 （周三下午）

报告地点: 闵行校区天美娱乐534报告厅

主办单位: 天美娱乐 科技处

 

报告人简介：Jean Lehmann博士毕业于瑞士洛桑大学物理系（现属瑞士洛桑理工天美EPFL）。在博士研究中首次发现遗传密码中anti-codon和codon的结合能与所对应的氨基酸大小有关联🥠，从而提出遗传密码起源的猜想👨‍🔬。2002年至2003年在瑞典卡罗林斯卡理工天美（KTH）继续从事对遗传密码起源的理论研究，提出GNC序列的RNA可以自转录，是建立遗传密码的核心规则。2004年至2009年在纽约洛克菲勒大学的Albert Libchaber教授研究室从事博士后研究，正式开始对其理论猜想进行实验验证工作🤦🏽‍♂️。自2010年受聘于法国巴黎十一大🏄🏻‍♀️，为微生物系副教授💲。目前除了设计并实验寻找与遗传密码起源有关的自催化RNA外，也探讨现代生物体中蛋白翻译转录规则，从而揭示生物进化如何抑制经典遗传密码转录规则👮🏻‍♂️👮🏻‍♂️，利用现代核糖体分子达到最高效解码与蛋白合成🧓🏿。

 

报告简介🗳：The catalytic site of most enzymes can efficiently deal with only one substrate. In contrast, the ribosome is capable of polymerizing at a similar rate at least 20 different kinds of amino acids from aminoacyl-tRNA carriers while using just one catalytic site, the peptidyl-transferase center (PTC). An induced-fit mechanism has been uncovered in the PTC, but a possible connection between this mechanism and the uniform handling of the substrates has not been investigated. We present an analysis of published ribosome structures supporting the hypothesis that the induced-fit eliminates unreactive rotamers predominantly populated for some A-site aminoacyl esters before induction. We show that this hypothesis is fully consistent with the wealth of kinetic data obtained with these substrates. Our analysis reveals that induction constrains the amino acids into a reactive conformation in a side-chain independent manner. It allows us to highlight the rationale of the PTC structural organization, which confers to the ribosome the very unusual ability to handle large as well as small substrates.