title: Structure analysis of the Staphylococcus aureus UDP-N-acetyl-mannosamine dehydrogenase Cap5O involved in capsular polysaccharide biosynthesis.
abstract: Bacterial UDP-sugar dehydrogenases are part of the biosynthesis pathway of extracellular polysaccharides. These compounds act as important virulence factors by protecting the cell from opsonophagocytosis and complement-mediated killing. In Staphylococcus aureus, the protein Cap5O catalyzes the oxidation of UDP-N-acetyl-mannosamine to UDP-N-acetyl-mannosaminuronic acid. Cap5O is crucial for the production of serotype 5 capsular polysaccharide that prevents the interaction of bacteria with both phagocytic and nonphagocytic eukaryotic cells. However, details of its catalytic mechanism remain unknown. We thus crystallized Cap5O and solved the first structure of an UDP-N-acetyl-mannosamine dehydrogenase. This study revealed that the catalytic cysteine makes a disulfide bond that has never been observed in other structurally characterized members of the NDP-sugar dehydrogenase family. Biochemical and mutagenesis experiments demonstrated that the formation of this disulfide bridge regulates the activity of Cap5O. We also identified two arginine residues essential for Cap5O activity. Previous data suggested that Cap5O is activated by tyrosine phosphorylation, so we characterized the phosphorylation site and examined the underlying regulatory mechanism.
authors: Laboratoire d'Enzymologie et Biochimie Structurales, Centre de Recherche de Gif, CNRS, 91198 Gif sur Yvette, France.
authors: Jakub
authors: J
authors: Gruszczyk
authors: Aurore
authors: A
authors: Fleurie
authors: Vanesa
authors: V
authors: Olivares-Illana
authors: Emmanuelle
authors: E
authors: Béchet
authors: Isabelle
authors: I
authors: Zanella-Cleon
authors: Solange
authors: S
authors: Moréra
authors: Philippe
authors: P
authors: Meyer
authors: Guillaume
authors: G
authors: Pompidor
authors: Richard
authors: R
authors: Kahn
authors: Christophe
authors: C
authors: Grangeasse
authors: Sylvie
authors: S
authors: Nessler
mesh_terms: D000595:Amino Acid Sequence; D002237:Carbohydrate Dehydrogenases / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray / Q000379:methods; D004220:Disulfides / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010084:Oxidation-Reduction; D010587:Phagocytosis; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D013211:Staphylococcus aureus / Q000201:enzymology*; D014443:Tyrosine / Q000737:chemistry
chemical_list: D004220:Disulfides; D011134:Polysaccharides; D019000:Phosphotyrosine; D014443:Tyrosine; D002237:Carbohydrate Dehydrogenases; C023228:UDP-N-acetylmannosamine dehydrogenase