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Title: High-resolution crystal structures of the solubilized domain of porcine cytochrome b{sub 5}

Crystal structures of the solubilized domain of cytochrome b{sub 5} from porcine liver were determined at sub-angstrom resolution in two crystal forms for both the oxidized and reduced states. The high-resolution structures provided information about the factors that are important for regulating the electronic properties of the haem group of cytochrome b{sub 5}. Mammalian microsomal cytochrome b{sub 5} has multiple electron-transfer partners that function in various electron-transfer reactions. Four crystal structures of the solubilized haem-binding domain of cytochrome b{sub 5} from porcine liver were determined at sub-angstrom resolution (0.76–0.95 Å) in two crystal forms for both the oxidized and reduced states. The high-resolution structures clearly displayed the electron density of H atoms in some amino-acid residues. Unrestrained refinement of bond lengths revealed that the protonation states of the haem propionate group may be involved in regulation of the haem redox properties. The haem Fe coordination geometry did not show significant differences between the oxidized and reduced structures. However, structural differences between the oxidized and reduced states were observed in the hydrogen-bond network around the axial ligand His68. The hydrogen-bond network could be involved in regulating the redox states of the haem group.
Authors:
 [1] ;  [2] ;  [1]
  1. Quantum Beam Science Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki 319-1195 (Japan)
  2. Faculty of Engineering, Ibaraki University, 4-12-1 Nakanarusawa, Hitachi, Ibaraki 316-8511 (Japan)
Publication Date:
OSTI Identifier:
22389074
Resource Type:
Journal Article
Resource Relation:
Journal Name: Acta Crystallographica. Section D: Biological Crystallography; Journal Volume: 71; Journal Issue: Pt 7; Other Information: PMCID: PMC4498607; PMID: 26143928; PUBLISHER-ID: mh5178; OAI: oai:pubmedcentral.nih.gov:4498607; Copyright (c) Hirano et al. 2015; This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
Denmark
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ATOMS; BOND LENGTHS; CRYSTAL STRUCTURE; CRYSTALS; DENSITY; ELECTRON DENSITY; ELECTRON TRANSFER; ELECTRONS; GEOMETRY; HYDROGEN; LIGANDS; LIVER; RESOLUTION