Influence of stereochemistry on proton transfer in protonated tripeptide models
| Autoři | |
|---|---|
| Rok publikování | 2012 |
| Druh | Článek v odborném periodiku |
| Časopis / Zdroj | Journal of Molecular Modeling |
| Fakulta / Pracoviště MU | |
| Citace | |
| www | http://link.springer.com/article/10.1007%2Fs00894-011-1116-2 |
| Doi | http://dx.doi.org/10.1007/s00894-011-1116-2 |
| Obor | Biochemie |
| Klíčová slova | Conformational rearrangement; Density functional theory; Protonated peptides; Proton transfer |
| Popis | Vectorial proton transfer among carbonyl oxygen atoms was studied in two models of tripeptide via quantum chemical calculations using the hybrid B3LYP functional and the 6-31++G** basis set. Two principal proton transfer pathways were found: a first path involving isomerization of the proton around the double bond of the carbonyl group, and a second based on the large conformational flexibility of the tripeptide model where all carbonyl oxygen atoms cooperate. The latter pathway has a rate-determining step energy barrier that is only around half of that for the first pathway. As conformational flexibility plays a crucial role in second pathway, the effect of attaching methyl groups to the alpha carbon atoms was studied. The results obtained are presented for all four possible stereochemical configurations. |
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