3] Structure and energy change in hemoglobin by hydrogen exchange labeling

Abstract

Publisher Summary Hydrogen exchange-labeling methods can in principle show which parts of hemoglobin are actively involved in the allosteric process and which are not. The approach derives from the local unfolding model. The local unfolding model for protein hydrogen exchange connects the exchange rate with local structural free energy. Thus the measurement of changes in hydrogen exchange (HX) rate may locate allosterically important changes and delineate the handling of allosteric energy in quantitative free-energy terms. The methods described in the chapter have made it possible to locate some of the important interactions and to measure their free-energy contribution to the overall allosteric transition. Results have demonstrated a quantitative relationship between structural free energy measured locally by these methods and globally by other established methods that involve the analysis of ligand-binding curves and the measurement of subunit-dissociation equilibria.