Dual frequency 2D-IR of peptide amide-A and amide-I modes.
- Resource Type
- Article
- Authors
- Rubtsov, I. V.; Wang, J.; Hochstrasser, R. M.
- Source
- Journal of Chemical Physics. 5/1/2003, Vol. 118 Issue 17, p7733. 4p. 4 Graphs.
- Subject
- *INFRARED spectra
*AMIDES
*PEPTIDES
*ELECTRONIC amplifiers
- Language
- ISSN
- 0021-9606
Dual frequency two-dimensional infrared (2D-IR) spectra were acquired with three IR fields, two at 3 and one at 6 μm from two pulses, creating a joint nonlinear response from both the amide-A (N-H) and the amide-I transitions of two model peptides AcAlaOMe and caprolactam. The 2D-IR spectra yield anharmonicities and correlations of inhomogeneous distributions. A positive correlation between the fundamental N-H mode frequency and its anharmonicity is found for the dipeptides. The amide-I frequencies are correlated with N-H mode frequencies and anticorrelated with the amide-I/N-H mode coupling. Structural implications of these results are discussed in relation to the anharmonic potential surface. [ABSTRACT FROM AUTHOR]