title: Heterodimeric nitrate reductase (NapAB) from Cupriavidus necator H16: purification, crystallization and preliminary X-ray analysis.
abstract: The periplasmic nitrate reductase from Cupriavidus necator (also known as Ralstonia eutropha) is a heterodimer that is able to reduce nitrate to nitrite. It comprises a 91 kDa catalytic subunit (NapA) and a 17 kDa subunit (NapB) that is involved in electron transfer. The larger subunit contains a molybdenum active site with a bis-molybdopterin guanine dinucleotide cofactor as well as one [4Fe-4S] cluster, while the small subunit is a di-haem c-type cytochrome. Crystals of the oxidized form of this enzyme were obtained using polyethylene glycol 3350 as precipitant. A single crystal grown at the High Throughput Crystallization Laboratory of the EMBL in Grenoble diffracted to beyond 1.5 A at the ESRF (ID14-1), which is the highest resolution reported to date for a nitrate reductase. The unit-cell parameters are a = 142.2, b = 82.4, c = 96.8 A, beta = 100.7 degrees, space group C2, and one heterodimer is present per asymmetric unit.
authors.affiliation: REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Coelho
authors.forename: Pablo J
authors.initials: PJ
authors.lastname: González
authors.forename: José
authors.initials: J
authors.lastname: Trincão
authors.forename: Ana L
authors.initials: AL
authors.lastname: Carvalho
authors.forename: Shabir
authors.initials: S
authors.lastname: Najmudin
authors.forename: Thomas
authors.initials: T
authors.lastname: Hettman
authors.forename: Stephan
authors.initials: S
authors.lastname: Dieckman
authors.forename: José J G
authors.initials: JJ
authors.lastname: Moura
authors.forename: Isabel
authors.initials: I
authors.lastname: Moura
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Romão
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification*; D003460:Crystallization / Q000379:methods; D018360:Crystallography, X-Ray; D020118:Cupriavidus necator / Q000302:isolation & purification*; D019281:Dimerization; D050901:Nitrate Reductase / Q000737:chemistry / Q000302:isolation & purification*; D021122:Protein Subunits / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D001426:Bacterial Proteins; D021122:Protein Subunits; D050901:Nitrate Reductase