title: Influence of extreme thermodynamic conditions and pyrite surfaces on peptide synthesis in aqueous media.
abstract: Free energy landscapes and reaction mechanisms underlying the synthesis of diglycine in water were studied computationally. It was found that amino acid activation by carbonyl sulfide, leading to the formation of a cyclic alpha-amino acid N-carboxyanhydride (NCA, or Leuchs anhydride), preferentially follows an indirect pathway that involves an isocyanate intermediate. Extreme temperature and pressure conditions accelerate peptidization greatly compared to the ambient bulk water environment and are shown to favor, in general, concerted versus stepwise mechanisms. Finally, a pyrite surface, FeS2 (001), is found to lower reaction barriers further by decreasing fluctuations and by assisting the preformation of the cyclic five-membered NCA ring due to scaffolding.
authors.affiliation: Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany. eduard.schreiner@theochem.rub.de
authors.forename: Eduard
authors.initials: E
authors.lastname: Schreiner
authors.forename: Nisanth N
authors.initials: NN
authors.lastname: Nair
authors.forename: Dominik
authors.initials: D
authors.lastname: Marx
mesh_terms: D003198:Computer Simulation; D003500:Cyclization; D006033:Glycylglycine / Q000138:chemical synthesis* / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D008956:Models, Chemical; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D011312:Pressure; D013440:Sulfides / Q000737:chemistry*; D013499:Surface Properties; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D010455:Peptides; D013440:Sulfides; D014867:Water; D006033:Glycylglycine; C011342:pyrite; D007501:Iron