A Novel Mechanism of Proton Transfer in Protonated Peptides

• Autoři: KULHÁNEK Petr; SCHLAG Edward W.; KOČA Jaroslav
• Rok publikování: 2003
• Druh: Článek v odborném periodiku
• Časopis / Zdroj: Journal of the American Chemical Society
• Fakulta / Pracoviště MU: Přírodovědecká fakulta
• www: http://dx.doi.org/10.1021/ja035800z
• Obor: Fyzikální chemie a teoretická chemie
• Klíčová slova: proton transfer; proton exchange; proton interaction; DFT
• Popis: The study presents quantum-chemical calculations on proton transfer in protonated N-acetylglycyl-N1-methylglycinamide (AGA) as a short oligopeptide model. All calculations employ the B3LYP functional and the 6-31++G** basis set. Two different mechanisms of proton transfer are discussed. The rate-determining step of the first mechanism exhibits an energy barrier of about 17.7 kcal/mol, and it is represented by an isomerization of the proton around the double bond of the carbonyl group. The second mechanism is based on the large conformational flexibility of AGA, where all carbonyl oxygens cooperate. The rate-determining step of this mechanism exhibits an energy barrier of only 8.3 kcal/mol.

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• Biomolekulární centrum