title: Fe-O2 bonding and oxyheme structure in myoglobin.
abstract: In the polarized electronic absorption spectrum of oxymyoglobin in single crystals, charge-transfer states involving orbitals of the iron and dioxygen ligand are defined as probes of oxyheme orbital structure and coordination geometry. The spectrum of sperm whale oxymyoglobin is diagnostic of a bent (formula: see text) oxheme coordination geometry with totally spin-paired, ground-state electronic configurations of the iron and of the dioxygen ligand. In contrast, Aplysia myoglobin is distinguishably different in oxyheme structure, indicating that the geometry of Fe-O2 bonding in heme proteins can be altered by the protein environment.
mesh_terms: D000818:Animals; D001048:Aplysia; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006418:Heme / Q000378:metabolism; D008024:Ligands; D008968:Molecular Conformation; D009211:Myoglobin / Q000378:metabolism; D010100:Oxygen; D013054:Spectrophotometry, Atomic; D013329:Structure-Activity Relationship; D014907:Whales
chemical_list: D008024:Ligands; D009211:Myoglobin; D006418:Heme; D010100:Oxygen