Structural fluctuations and conformational entropy in proteins: entropy balance in an intramolecular reaction in methemoglobin

Steinhoff, H.J., Schlitter, L., Redhardt, A., Husmeier, D. and Zander, N. (1992) Structural fluctuations and conformational entropy in proteins: entropy balance in an intramolecular reaction in methemoglobin. Biochimica et Biophysica Acta: Proteins and Proteomics, 1121(1-2), pp. 189-198.

Abstract

The reversible intramolecular binding of the distal histidine side chain to the heme iron in methemoglobin is of special interest due to the very large negative reaction entropy which overcompensates the large reaction enthalpy. It may be considered as a prominent example of the ability of proteins (including enzymes) to provide global entropy in a local process. In this work new experiments and model calculations are reported which aim at finding the structural elements contributing to the reaction entropy. Geometrical studies prove the implication of the 20 residue E-helix being shifted by more than 2Å. Vibrational entropies are calculated by a procedure derived from the method of Karplus and Kushik. It turns out that neither the histidine alone nor the complete E-helix contribute more than 15 per cent of the required entropy.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Husmeier, Professor Dirk
• Authors: Steinhoff, H.J., Schlitter, L., Redhardt, A., Husmeier, D., and Zander, N.
• College/School: College of Science and Engineering > School of Mathematics and Statistics > Statistics
• Journal Name: Biochimica et Biophysica Acta: Proteins and Proteomics
• ISSN: 1570-9639