title: Structures of sortase B from Staphylococcus aureus and Bacillus anthracis reveal catalytic amino acid triad in the active site.
abstract: Surface proteins attached by sortases to the cell wall envelope of bacterial pathogens play important roles during infection. Sorting and attachment of these proteins is directed by C-terminal signals. Sortase B of S. aureus recognizes a motif NPQTN, cleaves the polypeptide after the Thr residue, and attaches the protein to pentaglycine cross-bridges. Sortase B of B. anthracis is thought to recognize the NPKTG motif, and attaches surface proteins to m-diaminopimelic acid cross-bridges. We have determined crystal structure of sortase B from B. anthracis and S. aureus at 1.6 and 2.0 A resolutions, respectively. These structures show a beta-barrel fold with alpha-helical elements on its outside, a structure thus far exclusive to the sortase family. A putative active site located on the edge of the beta-barrel is comprised of a Cys-His-Asp catalytic triad and presumably faces the bacterial cell surface. A putative binding site for the sorting signal is located nearby.
authors.affiliation: Structural Biology Center and Midwest Center for Structural Genomics, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439 USA.
authors.forename: Rongguang
authors.initials: R
authors.lastname: Zhang
authors.forename: Ruiying
authors.initials: R
authors.lastname: Wu
authors.forename: Grazyna
authors.initials: G
authors.lastname: Joachimiak
authors.forename: Sarkis K
authors.initials: SK
authors.lastname: Mazmanian
authors.forename: Dominique M
authors.initials: DM
authors.lastname: Missiakas
authors.forename: Piotr
authors.initials: P
authors.lastname: Gornicki
authors.forename: Olaf
authors.initials: O
authors.lastname: Schneewind
authors.forename: Andrzej
authors.initials: A
authors.lastname: Joachimiak
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D019881:Aminoacyltransferases / Q000737:chemistry*; D001408:Bacillus anthracis / Q000201:enzymology*; D001426:Bacterial Proteins; D001665:Binding Sites; D018360:Crystallography, X-Ray; D003546:Cysteine Endopeptidases; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D013211:Staphylococcus aureus / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D019881:Aminoacyltransferases; C120542:sortase A; D003546:Cysteine Endopeptidases