Influence of stereochemistry on proton transfer in protonated tripeptide models
| Authors | |
|---|---|
| Year of publication | 2012 |
| Type | Article in Periodical |
| Magazine / Source | Journal of Molecular Modeling |
| MU Faculty or unit | |
| Citation | |
| Web | http://link.springer.com/article/10.1007%2Fs00894-011-1116-2 |
| Doi | http://dx.doi.org/10.1007/s00894-011-1116-2 |
| Field | Biochemistry |
| Keywords | Conformational rearrangement; Density functional theory; Protonated peptides; Proton transfer |
| Description | 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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