title: Crystallization and preliminary X-ray crystallographic analysis of a new crystal form of hydroxylamine oxidoreductase from Nitrosomonas europaea.
abstract: Hydroxylamine oxidoreductase (HAO) from Nitrosomonas europaea is a homotrimeric protein that catalyzes the oxidation of hydroxylamine to nitrite. Each monomer, with a molecular weight of 67.1 kDa, contains seven c-type hemes and one heme P460, the porphyrin ring of which is covalently linked to a tyrosine residue from an adjacent subunit. HAO was first crystallized and structurally characterized at a resolution of 2.8 A in 1997. The structure was solved in space group P6(3) and suffered from merohedral twinning. Here, a crystallization procedure is presented that yielded untwinned crystals belonging to space group P2(1)2(1)2, which diffracted to 2.25 A resolution and contained one trimer in the asymmetric unit. The unit-cell parameters were a = 140.7, b = 142.6, c = 107.4 A.
authors.affiliation: University of Minnesota, Minneapolis, USA.
authors.forename: Peder E
authors.initials: PE
authors.lastname: Cedervall
authors.forename: Alan B
authors.initials: AB
authors.lastname: Hooper
authors.forename: Carrie M
authors.initials: CM
authors.lastname: Wilmot
mesh_terms: D003460:Crystallization; D018360:Crystallography, X-Ray; D006418:Heme / Q000737:chemistry; D043370:Nitrosomonas europaea / Q000201:enzymology*; D010088:Oxidoreductases / Q000737:chemistry*; D020836:Protein Structure, Quaternary; D021122:Protein Subunits; D014443:Tyrosine / Q000737:chemistry
chemical_list: D021122:Protein Subunits; D014443:Tyrosine; D006418:Heme; D010088:Oxidoreductases; C021401:hydroxylamine dehydrogenase