"Induced-fit of the peptidyl-transferase center of the ribosome and conformational freedom of the esterified amino acids "Jean Lehmann(Institute for Integrative Biology of the Cell Université Paris-Sud,  France)  -2016.4.20

時間:     2016年4月20日  13:00
地點：    閔行校區 生命科學院534會議室
報告題目：Induced-fit of the peptidyl-transferase center of the ribosome and conformational freedom of the esterified amino acids
報告人： Jean Lehmann  Ph.D.
         Institute for Integrative Biology of the Cell
         Université Paris-Sud,  France
主持人：袁崇剛 教授

報告人簡介： Jean Lehmann  Ph.D. Associate professor / Lecturer, Université Paris-Sud, France
Dr. Lehmann got his Ph.D. in Institute of Condensed Matter Physics University of Lausanne. His postdoctoral training was in Institute of Theoretical Biophysics, Royal Institute of tech-nology (KTH) from 2002-2004 and Center for Studies in Physics and Biology, The Rockefeller University from 2004-2009. In 2009, he started his academic career as associate professor in Université Paris-Sud. His research interests were in Membrane Biology,

報告簡介：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 pep-tidyl-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 sub-strates 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 sub-strates.