title: Solution 1h NMR characterization of equilibrium heme orientational disorder with functional consequences in mouse neuroglobin.
abstract: The solution 1H NMR spectrum of oxidized (met) mouse neuroglobin, metNgb, demonstrates that it is low-spin and hexacoordinate with strong spectral similarities to ferricytochrome b5. The axial ligands are identified as His(F8) and His(E7), with the latter exhibiting an unstrained Fe-His bond. The presence of two sets of resonances is shown to arise from equilibrium heme orientational isomers ( approximately 2:1). The ligation of cyanide is shown to be extraordinarily slow with a factor approximately 2 difference in rate for the two heme orientations. Not only is Ngb the first mamalian globin with equilibrium heme disorder, but the disorder also has additional functional consequences.
authors.affiliation: Department of Chemistry, University of California-Davis, Davis, CA 95616, USA.
authors.forename: Weihong
authors.initials: W
authors.lastname: Du
authors.forename: Ray
authors.initials: R
authors.lastname: Syvitski
authors.forename: Sylvia
authors.initials: S
authors.lastname: Dewilde
authors.forename: Luc
authors.initials: L
authors.lastname: Moens
authors.forename: Gerd N
authors.initials: GN
authors.lastname: La Mar
mesh_terms: D000818:Animals; D005914:Globins / Q000737:chemistry*; D006418:Heme / Q000737:chemistry*; D051379:Mice; D009419:Nerve Tissue Proteins / Q000737:chemistry*; D000078787:Neuroglobin; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D012996:Solutions
chemical_list: D009419:Nerve Tissue Proteins; D000078787:Neuroglobin; D012996:Solutions; D006418:Heme; D005914:Globins