title: Dissection of hexosyl- and sialyltransferase domains in the bifunctional capsule polymerases from Neisseria meningitidis W and Y defines a new sialyltransferase family.
abstract: Crucial virulence determinants of disease causing Neisseria meningitidis species are their extracellular polysaccharide capsules. In the serogroups W and Y, these are heteropolymers of the repeating units (→6)-α-d-Gal-(1→4)-α-Neu5Ac-(2→)n in NmW and (→6)-α-d-Glc-(1→4)-α-Neu5Ac-(2→)n in NmY. The capsule polymerases, SiaDW and SiaDY, which synthesize these highly unusual polymers, are composed of two predicted GT-B fold domains separated by a large stretch of amino acids (aa 399-762). We recently showed that residues critical to the hexosyl- and sialyltransferase activity are found in the predicted N-terminal (aa 1-398) and C-terminal (aa 763-1037) GT-B fold domains, respectively. Here we use a mutational approach and synthetic fluorescent substrates to define the boundaries of the hexosyl- and sialyltransferase domains. Our results reveal that the active sialyltransferase domain extends well beyond the predicted C-terminal GT-B domain and defines a new glycosyltransferase family, GT97, in CAZy (Carbohydrate-Active enZYmes Database).
authors.affiliation: From the Institute of Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Angela
authors.initials: A
authors.lastname: Romanow
authors.affiliation: From the Institute of Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Keys
authors.affiliation: From the Institute of Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Stummeyer
authors.affiliation: From the Institute of Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Freiberger
authors.affiliation: UMR 7257, Centre National de la Recherche Scientifique, Aix-Marseille Université, 13288 Marseille, France, and the Department of Biological Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
authors.forename: Bernard
authors.initials: B
authors.lastname: Henrissat
authors.affiliation: From the Institute of Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany, gerardy-schahn.rita@mh-hannover.de.
authors.forename: Rita
authors.initials: R
authors.lastname: Gerardy-Schahn
mesh_terms: D000595:Amino Acid Sequence; D016667:Bacterial Capsules / Q000737:chemistry* / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry* / Q000145:classification / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006602:Hexosyltransferases / Q000737:chemistry* / Q000145:classification / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000737:chemistry* / Q000201:enzymology; D010802:Phylogeny; D011135:Polysaccharides, Bacterial / Q000737:chemistry; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012799:Sialyltransferases / Q000737:chemistry* / Q000145:classification / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011135:Polysaccharides, Bacterial; D006602:Hexosyltransferases; D012799:Sialyltransferases
keywords: Bioinformatics; Capsule Polymerases; Enzyme Catalysis; Fluorescence-based Testing of Glycosyltransferases; Glycosyltransferase; Hexosyltransferases; Neisseria meningitidis Serogroup W and Y; Phylogenetics; Polysaccharide; Sialyltransferases