title: Non-racemic mixture model: a computational approach.
abstract: The behavior of a slight chiral bias in favor of l-amino acids over d-amino acids was studied in an evolutionary mathematical model generating mixed chiral peptide hexamers. The simulations aimed to reproduce a very generalized prebiotic scenario involving a specified couple of amino acid enantiomers and a possible asymmetric amplification through autocatalytic peptide self-replication while forming small multimers of a defined length. Our simplified model allowed the observation of a small ascending but not conclusive tendency in the l-amino acid over the d-amino acid profile for the resulting mixed chiral hexamers in computer simulations of 100 peptide generations. This simulation was carried out by changing the chiral bias from 1% to 3%, in three stages of 15, 50 and 100 generations to observe any alteration that could mean a drastic change in behavior. So far, our simulations lead to the assumption that under the exposure of very slight non-racemic conditions, a significant bias between l- and d-amino acids, as present in our biosphere, was unlikely generated under prebiotic conditions if autocatalytic peptide self-replication was the main or the only driving force of chiral auto-amplification.
authors.affiliation: Department of Mathematics, Faculty of Sciences, Universidad Nacional Autonoma de México, Av. Universidad 3000 C.P. 04510 D.F., México.
authors.forename: Carlos
authors.initials: C
authors.lastname: Polanco
authors.affiliation: Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, C.P. 62209 Cuernavaca, Morelos, México.
authors.forename: Thomas
authors.initials: T
authors.lastname: Buhse
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D002384:Catalysis; D019418:Evolution, Chemical; D008962:Models, Theoretical; D010455:Peptides / Q000737:chemistry; D056692:Prebiotics; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D010455:Peptides; D056692:Prebiotics
keywords: amino acids; chiral asymmetry; origin of homochirality; prebiotic peptide formation