the dimeric proto-ribosome structural details and possible implications on the origin of life二聚proto-ribosome结构细节和可能影响生命的起源.pdf

Int. J. Mol. Sci. 2009, 10, 2921-2934; doi:10.3390/ijm OPEN ACCESS International Journal of Molecular Sciences ISSN 1422-0067 /journal/ijms Article The Dimeric Proto-Ribosome: Structural Details and Possible Implications on the Origin of Life Ilana Agmon The Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel; E-Mail: agmon1@; Tel. 972-4-8372956; Fax: 972-77-664-7774 Received: 1 June 2009 / Accepted: 25 June 2009 / Published: 30 June 2009 Abstract: A symmetric pocket-like entity, composed of two L-shaped RNA units, encircles the peptide synthesis site within the contemporary ribosome. This entity was suggested to be the vestige of a dimeric proto-ribosome, which could have formed spontaneously in the prebiotic world, catalyzing non-coded peptide bond formation and elongation. This structural element, beyond offering the initial step in the evolution of translation, is hypothesized here to be linked to the origin of life. By catalyzing the production of random peptide chains, the proto-ribosome could have enabled the formation of primary enzymes, launching a process of co-evolution of the translation apparatus and the proteins, thus presenting an alternative to the RNA world hypothesis. Keywords: proto-ribosome; origin of life; ribosome symmetrical r