title: Axial ligation of the high-potential heme center in an Arabidopsis cytochrome b561.
abstract: Arabidopsis has four putative, di-heme cytochrome b561 proteins, including one localized in the tonoplast (TCytb). From a comparative electron paramagnetic resonance (EPR), UV-Vis absorption and resonance Raman study, on wild type, H83A/H156A-TCytb and H83L/H156L-TCytb double mutants, it follows that the H83 and H156 residues are binding one of the two hemes. These measurements show that the high-potential heme site is situated at the cytoplasmic side of the membrane and allow the unambiguous differentiation between two models on the heme localization in cytochrome b561 proteins.
authors.affiliation: Department of Physics, University of Antwerp, Belgium.
authors.forename: Filip
authors.initials: F
authors.lastname: Desmet
authors.forename: Alajos
authors.initials: A
authors.lastname: Bérczi
authors.forename: László
authors.initials: L
authors.lastname: Zimányi
authors.forename: Han
authors.initials: H
authors.lastname: Asard
authors.forename: Sabine
authors.initials: S
authors.lastname: Van Doorslaer
mesh_terms: D019943:Amino Acid Substitution; D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000737:chemistry*; D003573:Cytochrome b Group / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D006418:Heme / Q000737:chemistry*; D006639:Histidine / Q000737:chemistry; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000737:chemistry; D010084:Oxidation-Reduction; D011994:Recombinant Proteins / Q000737:chemistry; D013053:Spectrophotometry; D013059:Spectrum Analysis, Raman; D014617:Vacuoles / Q000201:enzymology
chemical_list: D029681:Arabidopsis Proteins; D003573:Cytochrome b Group; D050505:Mutant Proteins; D011994:Recombinant Proteins; C023646:cytochrome b561; D006418:Heme; D006639:Histidine