Application of linear free energy relations to protein conformational changes: the quaternary structural change of hemoglobin.
The transition state for the R in equilibrium with T quaternary conformational change of hemoglobin has thermodynamic properties much closer to those of the R conformation than to those of the T conformation. This finding is based on a comparison of activation and equilibrium enthalpy and entropy changes and on the observation of a linear free energy relationship between quaternary rate and equilibrium constants. A previous theoretical study [Janin, J. & Wodak, S. J. (1985) Biopolymers 24, 509-526], using a highly simplified energy function, suggests that the R-like transition state is the result of a reaction pathway with the maximum buried surface area between alpha beta dimers.
Eaton
W A
WA
Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
Henry
E R
ER
Hofrichter
J
J
D000494:Allosteric Regulation; D006454:Hemoglobins / Q000737:chemistry*; D006801:Humans; D007700:Kinetics; D046911:Macromolecular Substances; D011487:Protein Conformation; D013816:Thermodynamics
D006454:Hemoglobins; D046911:Macromolecular Substances