Gas phase H/D exchange of sodiated amino acids: Why do we see zwitterions?

• DOI: 10.1016/j.jasms.2005.08.017
• Publication Date: 2005-12-19T15:52:07Z
• Authors: Marko Rožman; Branimir Bertoša; Leo Klasinc; Dunja Srzić
• Keywords: H/D exchange; Models, Molecular; H/D exchange ; sodiated amino acids ; reaction mechanism; Sodium; Molecular Conformation; Water; Deuterium; 01 natural sciences; 0104 chemical sciences; Chemistry; sodiated amino acids; Computer Simulation; reaction mechanism; Amino Acids; H/D exchange; sodiated amino acids; reaction mechanism; Software

The gas-phase interaction of sodiated amino acids and acid methyl esters with various deuterium donors is investigated by combining results H/D exchange reactions those from density functional theory molecular dynamics calculations. Discrepancy between experimentally theoretically obtained structures for sodium cationized explained donor caused perturbation the most stable conformation. Detailed study mechanism on shows that reaction preceded a multistep quasi-isoenergetic transition (perturbation) charge solvated to zwitterionic structure in acid. Although computation refers system AlaNa(+) D(2)O, these mechanisms apply all acids, except where side-chain group takes part process. suggested applies also other such as CD(3)OD or even ND(3) indicates single water molecule suffices convert form.