The two-dimensional IR nonlinear spectroscopy of a cyclic penta-peptide in relation to its three-dimensional structure

Proc Natl Acad Sci U S A. 1999 Mar 2;96(5):2036-41. doi: 10.1073/pnas.96.5.2036.

Abstract

A form of two-dimensional (2D) vibrational spectroscopy, which uses two ultrafast IR laser pulses, is used to examine the structure of a cyclic penta-peptide in solution. Spectrally resolved cross peaks occur in the off-diagonal region of the 2D IR spectrum of the amide I region, analogous to those in 2D NMR spectroscopy. These cross peaks measure the coupling between the different amide groups in the structure. Their intensities and polarizations relate directly to the three-dimensional structure of the peptide. With the help of a model coupling Hamiltonian, supplemented by density functional calculations, the spectra of this penta-peptide can be regenerated from the known solution phase structure. This 2D-IR measurement, with an intrinsic time resolution of less than 1 ps, could be used in all time regimes of interest in biology.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Computing Methodologies
  • Models, Molecular
  • Nuclear Magnetic Resonance, Biomolecular
  • Oligopeptides / chemistry*
  • Peptides, Cyclic / chemistry*
  • Protein Conformation*
  • Spectrophotometry, Infrared / methods
  • Vibration

Substances

  • Oligopeptides
  • Peptides, Cyclic