title: Proton NMR study of the influence on iron oxidation/ligation/spin state on the heme orientational preference in myoglobin.
abstract: Proton nuclear magnetic resonance spectroscopy has been utilized to demonstrate that the degree of heme orientational disorder within a given myoglobin protein matrix can be a sensitive function of the oxidation/ligation/spin state of the heme iron. For sperm whale deuterohemin-reconstituted myoglobin, the equilibrium was found to strongly favor (5.7 to 7.8 kJ/mol) the X-ray characterized heme orientation in all six-coordinate states, but with a considerable reduction in preference (to 1.6 kJ/mol) in the five-coordinate deoxy state. In native yellow fin tuna myoglobin, changes in heme orientational preferences of approximately 3 kJ/mol occur even between two six-coordinate ferric states differing solely in spin states.
authors.affiliation: Department of Chemistry, University of California, Davis 95616.
authors.forename: G N
authors.initials: GN
authors.lastname: La Mar
authors.forename: W S
authors.initials: WS
authors.lastname: Smith
authors.forename: N L
authors.initials: NL
authors.lastname: Davis
authors.forename: D L
authors.initials: DL
authors.lastname: Budd
authors.forename: M J
authors.initials: MJ
authors.lastname: Levy
mesh_terms: D000818:Animals; D003461:Crystallography; D006418:Heme; D009682:Magnetic Resonance Spectroscopy; D009038:Motion; D009211:Myoglobin; D010084:Oxidation-Reduction; D014907:Whales
chemical_list: D009211:Myoglobin; D006418:Heme