Chemical evolution of biomolecule building blocks. Can thermodynamics explain the accumulation of glycine in the prebiotic ocean?

Milán Szori, Balázs Jójárt, Róbert Izsák, Kornél Szori, Imre G Csizmadia, Béla Viskolcz

Department of Chemical Informatics, Faculty of Education, University of Szeged, Boldogasszony sgt. 6, Szeged 6725, Hungary. milan@jgypk.u-szeged.hu

Physical chemistry chemical physics : PCCP 2011 Apr 28

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It has always been a question of considerable scientific interest why amino acids (and other biomolecule building blocks) formed and accumulated in the prebiotic ocean. In this study, we suggest an answer to this question for the simplest amino acid, glycine. We have shown for the first time that classical equilibrium thermodynamics can explain the most likely selection of glycine (and the derivative of its dipeptide) in aqueous media, although glycine is not the lowest free energy structure among all (404) possible constitutional isomers. Species preceding glycine in the free energy order are either supramolecular complexes of small molecules or such molecules likely to dissociate and thus get back to the gas phase. Then, 2-hydroxyacetamide condensates yielding a thermodynamically favored derivative of glycine dipeptide providing an alternative way for peptide formation. It is remarkable that a simple equilibrium thermodynamic model can explain the accumulation of glycine and provide a reason for the importance of water in the formation process.

Citation

Milán Szori, Balázs Jójárt, Róbert Izsák, Kornél Szori, Imre G Csizmadia, Béla Viskolcz. Chemical evolution of biomolecule building blocks. Can thermodynamics explain the accumulation of glycine in the prebiotic ocean? Physical chemistry chemical physics : PCCP. 2011 Apr 28;13(16):7449-58