title: The 2.8 A structure of hydroxylamine oxidoreductase from a nitrifying chemoautotrophic bacterium, Nitrosomonas europaea.
abstract: The 2.8 A crystal structure of hydroxylamine oxidoreductase of a nitrifying chemoautotrophic bacterium, Nitrosomonas europaea, is described. Twenty-four haems lie in the centre bottom of the trimeric molecule, localized in four clusters within each monomer. The haem clusters within the trimer are aligned to form a ring that has inlet and outlet sites. The inlet is occupied by a novel haem, P460, and there are two possible outlet sites per monomer formed by paired haems lying within a cavity or cleft on the protein surface. The structure suggests pathways by which electron transfer may occur through the precisely arranged haems and provides a framework for the interpretation of previous and future biochemical and genetic observations.
authors.affiliation: Department of Life Science, Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Igarashi
authors.forename: H
authors.initials: H
authors.lastname: Moriyama
authors.forename: T
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Y
authors.initials: Y
authors.lastname: Fukumori
authors.forename: N
authors.initials: N
authors.lastname: Tanaka
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D004579:Electron Transport; D006418:Heme / Q000031:analogs & derivatives* / Q000737:chemistry; D019811:Hydroxylamine; D006898:Hydroxylamines / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009606:Nitrosomonas / Q000201:enzymology*; D010088:Oxidoreductases / Q000737:chemistry*; D011487:Protein Conformation; D012984:Software; D013499:Surface Properties
chemical_list: D006898:Hydroxylamines; C035762:heme P-460; D019811:Hydroxylamine; D006418:Heme; D010088:Oxidoreductases; C021401:hydroxylamine dehydrogenase