Dynamics of a Small Globular Protein in Terms of Low-Frequency Vibrational Modes
Abstract
Normal modes of low-frequency vibrations are calculated for a small globular protein, bovine pancreatic trypsin inhibitor. In modes with frequencies below 120 cm-1 the protein molecule behaves like a continuous elastic body. Most modes with frequencies above 50 cm-1 are shown to behave harmonically within the range of thermal fluctuations at room temperature. Those with frequencies below 50 cm-1 show some anharmonicity. Magnitudes of displacements of atoms are mainly determined by the modes with frequencies below 30 cm-1. These very-low-frequency modes contribute significantly to the entropy of the system. The dynamic structure of the globular protein is described as a superposition of harmonic high-frequency motions and coupled anharmonic low-frequency motions of collective variables corresponding to the normal modes of vibration.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- June 1983
- DOI:
- 10.1073/pnas.80.12.3696
- Bibcode:
- 1983PNAS...80.3696G