title: The sulfur oxygenase reductase from Acidianus ambivalens is an icosatetramer as shown by crystallization and Patterson analysis.
abstract: The sulfur oxygenase reductase (SOR) is the initial enzyme in the aerobic sulfur metabolism of the thermoacidophilic and chemolithoautotrophic crenarchaeote Acidianus ambivalens. Single colorless polyhedral crystals were obtained under two crystallization conditions from SOR preparations heterologously overproduced in Escherichia coli. They belonged to space-group I4 and diffraction data were collected up to 1.7 A resolution. Their Patterson symmetry shows additional 4-, 3- and 2-fold non-crystallographic symmetry rotation axes, characteristic of the point group 432. Taking into account the molecular mass of SOR, the crystal unit cell volume, the non-crystallographic symmetry operators and previous electron microscopy studies of the SOR, it was deduced that the quaternary structure of the functionally active enzyme is an icosatetramer with 871 kDa molecular mass.
authors.affiliation: Institute of Microbiology and Genetics, Darmstadt University of Technology, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Urich
authors.forename: Ricardo
authors.initials: R
authors.lastname: Coelho
authors.forename: Arnulf
authors.initials: A
authors.lastname: Kletzin
authors.forename: Carlos
authors.initials: C
authors.lastname: Frazao
mesh_terms: D041541:Acidianus / Q000201:enzymology* / Q000235:genetics; D000945:Antigens, Differentiation, T-Lymphocyte / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D048429:Cell Size; D003460:Crystallization; D004926:Escherichia coli / Q000235:genetics; D006418:Heme / Q000737:chemistry / Q000378:metabolism; D060889:Inducible T-Cell Co-Stimulator Protein; D008970:Molecular Weight; D010088:Oxidoreductases / Q000737:chemistry* / Q000302:isolation & purification; D050862:Oxidoreductases Acting on Sulfur Group Donors; D013455:Sulfur / Q000737:chemistry / Q000378:metabolism
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D019843:Archaeal Proteins; D060889:Inducible T-Cell Co-Stimulator Protein; D006418:Heme; D013455:Sulfur; D010088:Oxidoreductases; D050862:Oxidoreductases Acting on Sulfur Group Donors; C058771:soR protein, Acidianus ambivalens