title: Solution structure of the 30 kDa polysulfide-sulfur transferase homodimer from Wolinella succinogenes.
abstract: The periplasmic polysulfide-sulfur transferase (Sud) protein encoded by Wolinella succinogenes is involved in oxidative phosphorylation with polysulfide-sulfur as a terminal electron acceptor. The polysulfide-sulfur is covalently bound to the catalytic Cys residue of the Sud protein and transferred to the active site of the membranous polysulfide reductase. The solution structure of the homodimeric Sud protein has been determined using heteronuclear multidimensional NMR techniques. The structure is based on NOE-derived distance restraints, backbone hydrogen bonds, and torsion angle restraints as well as residual dipolar coupling restraints for a refinement of the relative orientation of the monomer units. The monomer structure consists of a five-stranded parallel beta-sheet enclosing a hydrophobic core, a two-stranded antiparallel beta-sheet, and six alpha-helices. The dimer fold is stabilized by hydrophobic residues and ion pairs found in the contact area between the two monomers. Similar to rhodanese enzymes, Sud catalyzes the transfer of the polysulfide-sulfur to the artificial acceptor cyanide. Despite their similar functions and active sites, the amino acid sequences and structures of these proteins are quite different.
authors.affiliation: Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, J. W. Goethe-University, Marie-Curie-Strasse 9, D-60439 Frankfurt am Main, Germany.
authors.forename: Yi-Jan
authors.initials: YJ
authors.lastname: Lin
authors.forename: Felician
authors.initials: F
authors.lastname: Dancea
authors.forename: Frank
authors.initials: F
authors.lastname: Löhr
authors.forename: Oliver
authors.initials: O
authors.lastname: Klimmek
authors.forename: Stefania
authors.initials: S
authors.lastname: Pfeiffer-Marek
authors.forename: Michael
authors.initials: M
authors.lastname: Nilges
authors.forename: Hans
authors.initials: H
authors.lastname: Wienk
authors.forename: Achim
authors.initials: A
authors.lastname: Kröger
authors.forename: Heinz
authors.initials: H
authors.lastname: Rüterjans
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D019281:Dimerization; D008969:Molecular Sequence Data; D008970:Molecular Weight; D019906:Nuclear Magnetic Resonance, Biomolecular; D010088:Oxidoreductases / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D012996:Solutions; D013329:Structure-Activity Relationship; D013440:Sulfides / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*; D013466:Sulfurtransferases / Q000737:chemistry*; D016968:Wolinella / Q000201:enzymology*
chemical_list: D012996:Solutions; D013440:Sulfides; D013455:Sulfur; C032915:polysulfide; D010088:Oxidoreductases; C074883:polysulfide reductase; D013466:Sulfurtransferases