title: Paramagnetic properties of the low- and high-spin states of yeast cytochrome c peroxidase.
abstract: Here we describe paramagnetic NMR analysis of the low- and high-spin forms of yeast cytochrome c peroxidase (CcP), a 34 kDa heme enzyme involved in hydroperoxide reduction in mitochondria. Starting from the assigned NMR spectra of a low-spin CN-bound CcP and using a strategy based on paramagnetic pseudocontact shifts, we have obtained backbone resonance assignments for the diamagnetic, iron-free protein and the high-spin, resting-state enzyme. The derived chemical shifts were further used to determine low- and high-spin magnetic susceptibility tensors and the zero-field splitting constant (D) for the high-spin CcP. The D value indicates that the latter contains a hexacoordinate heme species with a weak field ligand, such as water, in the axial position. Being one of the very few high-spin heme proteins analyzed in this fashion, the resting state CcP expands our knowledge of the heme coordination chemistry in biological systems.
authors.affiliation: Jean Jeener NMR Centre, Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.
authors.forename: Sophie
authors.initials: S
authors.lastname: Vanwetswinkel
authors.forename: Nico A J
authors.initials: NA
authors.lastname: van Nuland
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Volkov
mesh_terms: D003578:Cytochrome-c Peroxidase / Q000032:analysis / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D006420:Hemeproteins / Q000737:chemistry*; D008928:Mitochondria / Q000201:enzymology; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D015003:Yeasts / Q000201:enzymology*
chemical_list: D006420:Hemeproteins; D003578:Cytochrome-c Peroxidase