title: Formation of RNA phosphodiester bond by histidine-containing dipeptides.
abstract: A new scenario for prebiotic formation of nucleic acid oligomers is presented. Peptide catalysis is applied to achieve condensation of activated RNA monomers into short RNA chains. As catalysts, L-dipeptides containing a histidine residue, primarily Ser-His, were used. Reactions were carried out in self-organised environment, a water-ice eutectic phase, with low concentrations of reactants. Incubation periods up to 30 days resulted in the formation of short oligomers of RNA. During the oligomerisation, an active intermediate (dipeptide-mononucleotide) is produced, which is the reactive species. Details of the mechanism and kinetics, which were elucidated with a set of control experiments, further establish that the imidazole side chain of a histidine at the carboxyl end of the dipeptide plays a crucial role in the catalysis. These results suggest that this oligomerisation catalysis occurs by a transamination mechanism. Because peptides are much more likely products of spontaneous condensation than nucleotide chains, their potential as catalysts for the formation of RNA is interesting from the origin-of-life perspective. Finally, the formation of the dipeptide-mononucleotide intermediate and its significance for catalysis might also be viewed as the tell-tale signs of a new example of organocatalysis.
authors.affiliation: FLinT Center, Institut for Fysik, Kemi og Farmaci (IFKF), University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark.
authors.forename: Rafał
authors.initials: R
authors.lastname: Wieczorek
authors.forename: Mark
authors.initials: M
authors.lastname: Dörr
authors.forename: Agata
authors.initials: A
authors.lastname: Chotera
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Luisi
authors.forename: Pierre-Alain
authors.initials: PA
authors.lastname: Monnard
mesh_terms: D002384:Catalysis; D004151:Dipeptides / Q000737:chemistry*; D007053:Ice / Q000032:analysis; D007700:Kinetics; D000069497:Origin of Life; D012313:RNA / Q000138:chemical synthesis*; D012265:Ribonucleotides / Q000737:chemistry*
chemical_list: D004151:Dipeptides; D007053:Ice; D012265:Ribonucleotides; C422849:seryl-histidine; D012313:RNA