title: Glutathione as a prebiotic answer to α-peptide based life.
abstract: The energetics of peptide bond formation is an important factor not only in the design of chemical peptide synthesis, but it also has a role in protein biosynthesis. In this work, quantum chemical calculations at 10 different levels of theory including G3MP2B3 were performed on the energetics of glutathione formation. The strength of the peptide bond is found to be closely related to the acid strength of the to-be N-terminal and the basicity of the to-be C-terminal amino acid. It is shown that the formation of the first peptide activates the amino acid for the next condensation step, manifested in bacterial protein synthesis where the first step is the formation of an N-formylmethionine dipeptide. The possible role of glutathione in prebiotic molecular evolution is also analyzed. The implications of the thermodynamics of peptide bond formation in prebiotic peptide formation as well as in the preference of α- instead of β- or γ-amino acids are discussed. An empirical correction is proposed for the compensation of the error due to the incapability of continuum solvation models in describing the change of the first solvation shell when a peptide bond is formed from two zwitterions accompanied by the disappearance of one ion pair.
authors.affiliation: Department of Chemical Informatics, Faculty of Education, University of Szeged , Boldogasszony sgt. 6, Szeged, Hungary -6725.
authors.forename: Béla
authors.initials: B
authors.lastname: Fiser
authors.forename: Balázs
authors.initials: B
authors.lastname: Jójárt
authors.forename: Milán
authors.initials: M
authors.lastname: Szőri
authors.forename: György
authors.initials: G
authors.lastname: Lendvay
authors.forename: Imre G
authors.initials: IG
authors.lastname: Csizmadia
authors.forename: Béla
authors.initials: B
authors.lastname: Viskolcz
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry; D005978:Glutathione / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D011789:Quantum Theory; D013816:Thermodynamics
chemical_list: D001426:Bacterial Proteins; D010455:Peptides; D005978:Glutathione