title: Atomic resolution structure of pseudoazurin from the methylotrophic denitrifying bacterium Hyphomicrobium denitrificans: structural insights into its spectroscopic properties.
abstract: The crystal structure of native pseudoazurin (HdPAz) from the methylotrophic denitrifying bacterium Hyphomicrobium denitrificans has been determined at a resolution of 1.18 A. After refinement with SHELX employing anisotropic displacement parameters and riding H atoms, R(work) and R(free) were 0.135 and 0.169, respectively. Visualization of the anisotropic displacement parameters as thermal ellipsoids provided insight into the atomic motion within the perturbed type 1 Cu site. The asymmetric unit includes three HdPAz molecules which are tightly packed by head-to-head cupredoxin dimer formation. The shape of the Cu-atom ellipsoid implies significant vibrational motion diagonal to the equatorial xy plane defined by the three ligands (two His and one Cys). The geometric parameters of the type 1 Cu site in the HdPAz structure differ unambiguously from those of other pseudoazurins. It is demonstrated that their structural aspects are consistent with the unique visible absorption spectrum.
authors.affiliation: Bioinorganic Chemistry Laboratory, Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hira
authors.forename: Masaki
authors.initials: M
authors.lastname: Nojiri
authors.forename: Shinnichiro
authors.initials: S
authors.lastname: Suzuki
mesh_terms: D016880:Anisotropy; D001400:Azurin / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D003460:Crystallization; D018360:Crystallography, X-Ray; D004579:Electron Transport; D020582:Hyphomicrobium / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D013054:Spectrophotometry, Atomic
chemical_list: C047163:pseudoazurin; D001400:Azurin; D003300:Copper