Dissolved Divalent Metal and pH Effects on Amino Acid Polymerization: A Thermodynamic Evaluation.

摘要: Polymerization of amino acids is a fundamentally important step for the chemical evolution life. Nevertheless, its response to changing environmental conditions has not yet been well understood because lack reliable quantitative information. For thermodynamics, detailed prediction over diverse combinations temperature and pH made only few acid–peptide systems. This study used recently reported thermodynamic dataset polymerization simplest acid “glycine (Gly)” short peptides (di-glycine tri-glycine) examine structural characteristics that control dependence polymerization. Results showed dependency strongly controlled by intramolecular distance between carboxyl groups in an structure, although side-chain group role minor. The behavior Gly earlier literature therefore expected be typical feature those α-amino acids. Equilibrium calculations were conducted effects dissolved metals as function on monomer–polymer equilibria Gly. shift toward monomer side, particularly at neutral alkaline pH. Metals form weak interaction with (e.g., Mg2+) have no noticeable influence polymerization, strong engenders significant decrease equilibrium concentrations peptides. Considering their interactions metals, it can similar responses addition are applicable Neutral aqueous environments having high affinity Cu2+) beneficial places peptide bond formation primitive Earth.