Two-dimensional Infrared Spectroscopy of a Model Peptide Homodimer
- Received Date: 2007-01-15
- Rev Recd Date: 2007-03-16
- Two-dimensional infrared spectroscopy, Peptide homodimer, Vibrational coupling, Transitiondipole coupling, Exciton model
Abstract: A pair of peptide groups in space, as modeled by formamide dimer, was used to evaluate vibrational coupling between the amide-I modes and the spatial behavior of the coupling using ab initio quantum chemical calculations. It was found that the coupling between two C=O groups, which is electrostatic in nature, is still quite signiˉcant as the intermolecular distance reaches 10 oA. One- and two-dimensional infrared spectra of the dimer at several conˉgurations were calculated using a vibrational exciton model that utilizes the abinitio computation-obtained parameters. The distance dependence of the coupling is dramatically shown in both the 1D and 2D infrared spectral features. The results suggest that the C=O stretching modes in polypeptide can be coupled and their states can be delocalized over quite a long distance in space.
|Citation:||Jian-ping Wang. Two-dimensional Infrared Spectroscopy of a Model Peptide Homodimer[J]. Chinese Journal of Chemical Physics , 2007, 20(5): 509-517. doi: 10.1088/1674-0068/20/05/509-517|