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The RNA world hypothesis assumes that life arose from ancestral RNA molecules, which stored genetic information and catalyzed chemical reac-tions. Although RNA catalysis was believed to be restricted to phosphate chemistry, it is now established that the RNA has much wider catalytic capacities. | Adenine a hairpin ribozyme cofactor - high-pressure and competition studies Myriam Ztouti1 z Hussein Kaddour1 z Francisco Miralles1 Christophe Simian1 Jacques Vergne1 Guy Herve2 and Marie-Christine Maurel1 1 Acides Nucleiques et Biophotonique FRE 3207 CNRS Fonctions et Interactions des Acides Nucleiques UPMC Universite Paris 06 France 2 Laboratoire Proteines Biochimie Structurale et Fonctionnelle FRE 2852 CNRS UPMC Universite Paris 06 France Keywords adenine catalysis hairpin ribozyme high pressure RNA Correspondence M.-C. Maurel Acides Nucleiques et Biophotonique ANBioPhy Universite Pierre et Marie Curie Tour 42- 42-43 -5eme etage 4 place Jussieu 75252 Paris Cedex 05 France Fax 33 1 44 27 99 16 Tel 33 1 44 27 40 21 E-mail marie-christine.maurel@upmc.fr These authors contributed equally to this work Received 28 November 2008 revised 29 January 2009 accepted 25 February 2009 doi 10.1111 j.1742-4658.2009.06983.x The RNA world hypothesis assumes that life arose from ancestral RNA molecules which stored genetic information and catalyzed chemical reactions. Although RNA catalysis was believed to be restricted to phosphate chemistry it is now established that the RNA has much wider catalytic capacities. In this respect we devised in a previous study two hairpin ribozymes adenine-dependent hairpin ribozyme 1 and adenine-dependent hairpin ribozyme 2 that require adenine as cofactor for their reversible self-cleavage. We have now used high hydrostatic pressure to investigate the role of adenine in the catalytic activity of adenine-dependent hairpin ribozyme 1. High-pressure studies are of interest because they make it possible to determine the volume changes associated with the reactions which in turn reflect the conformational modifications and changes in hydration involved in the catalytic mechanism. They are also relevant in the context of piezophilic organisms as well as in relation to the extreme conditions that prevailed at the origin of life. Our results indicate .
