title: Cloning, expression, purification, crystallization and preliminary crystallographic analysis of NifH1 from Methanocaldococcus jannaschii.
abstract: Nitrogen fixation is catalyzed by the nitrogenase complex in Azotobacter, which is composed of dinitrogenase and dinitrogenase reductase. Dinitrogenase is an α(2)β(2) heterotetramer of the proteins NifD and NifK. Dinitrogenase reductase is a homodimer of the protein NifH. The expression of NifD/K and NifH nitrogenase homologues (named NflD/K and NflH for Nif-like D and H, respectively) has been detected in the non-nitrogen-fixing hyperthermophilic methanogen Methanocaldococcus jannaschii. Solving the structure of MjNifH1 may help in better understanding its function and may supply some clues to understanding the evolution of nitrogenase. The full-length protein with an additional His(6) tag at the C-terminus was expressed, purified and crystallized by the hanging-drop vapour-diffusion method at 287 K. An X-ray diffraction data set was collected to a resolution of 3.3 Å. The crystal belonged to space group P4(1)32, with unit-cell parameters a = b = c = 139.45 Å, and was estimated to contain one protein molecule per asymmetric unit.
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230027, People's Republic of China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
authors.forename: Ye
authors.initials: Y
authors.lastname: Yuan
authors.forename: Jinming
authors.initials: J
authors.lastname: Ma
authors.forename: Yongxiang
authors.initials: Y
authors.lastname: Gao
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry*; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D015870:Gene Expression; D010088:Oxidoreductases / Q000737:chemistry*; D051922:PII Nitrogen Regulatory Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D019843:Archaeal Proteins; D051922:PII Nitrogen Regulatory Proteins; D010088:Oxidoreductases; C029130:nitrogenase reductase