A Novel Aproach to Prebiotic Protein Synthesis一种新的益生元蛋白的合成方法.pptVIP

A Novel Approach to Prebiotic Protein Synthesis Malcolm E. Schrader Department of Inorganic and Analytical Chemistry The Hebrew University of Jerusalem ILASOL 25th Annual Meeting 25 Dec 2011 Outline In today’s talk I explore additional consequences of my approach claiming that prebiotic small atmospheric molecules concentrated and reacted on land rather than in the oceans. I first point out some problems with the popular notion that polypeptides, or proteins, were formed prebiotically from condensation of amino acids. I then propose, as an alternative, a polymerization based on an extension of our previously proposed mechanism for prebiotic synthesis of RNA. Conventional Approach Condensation of aminoacids, RCH(NH2)COOH, to form polypeptide. For example, glycene condensation (R=H) HCHNH2COOH + HNHHCHCOOH → HCHNH2CONHCH2COOH +H2O where CONH contains the amide bond. Where did amino acid come from? Miller’s Experiments Miller duplicated, in the laboratory, a reducing atmosphere, essentially as advocated by Urey, consisting of H2, CH4, NH3, and H20. With tungsten electrodes in an all glass system, water was boiled in a 500 ml. flask, and its vapor mixed with these reducing gases in a 5 l. flask, where sparking took place. Choice of Electrical Sparks Miller chose electrical sparks for his excitation source in his pioneering experiments. The reason for this choice was apparently mainly for experimental convenience. The assumption was that if it worked with sparks it would probably work with other energy inputs as well. Leakage of Air Modern vacuum techniques have emphasized the futility of preventing seemingly small, but sometimes highly significant, leakages of air into ordinary reaction apparatus. Nowadays, an all glass an