title: Identification of a second catalytically active trans-sialidase in Trypanosoma brucei.
abstract: The procyclic stage of Trypanosoma brucei is covered by glycosylphosphatidylinositol (GPI)-anchored surface proteins called procyclins. The procyclin GPI anchor contains a side chain of N-acetyllactosamine repeats terminated by sialic acids. Sialic acid modification is mediated by trans-sialidases expressed on the parasite's cell surface. Previous studies suggested the presence of more than one active trans-sialidases, but only one has so far been reported. Here we cloned and examined enzyme activities of four additional trans-sialidase homologs, and show that one of them, Tb927.8.7350, encodes another active trans-sialidase, designated as TbSA C2. In an in vitro assay, TbSA C2 utilized α2-3 sialyllactose as a donor, and produced an α2-3-sialylated product, suggesting that it is an α2-3 trans-sialidase. We suggest that TbSA C2 plays a role in the sialic acid modification of the trypanosome cell surface.
authors: Department of Immunoregulation, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
authors: Fumiki
authors: F
authors: Nakatani
authors: Yasu S
authors: YS
authors: Morita
authors: Hisashi
authors: H
authors: Ashida
authors: Kisaburo
authors: K
authors: Nagamune
authors: Yusuke
authors: Y
authors: Maeda
authors: Taroh
authors: T
authors: Kinoshita
mesh_terms: D000606:Amino Sugars / Q000737:chemistry; D002384:Catalysis; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017261:Glycosylphosphatidylinositols / Q000737:chemistry / Q000378:metabolism; D009154:Mutation; D019158:N-Acetylneuraminic Acid / Q000737:chemistry / Q000378:metabolism*; D009439:Neuraminidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014346:Trypanosoma brucei brucei / Q000201:enzymology* / Q000235:genetics
chemical_list: D000606:Amino Sugars; D006023:Glycoproteins; D017261:Glycosylphosphatidylinositols; C000458:N-acetyllactosamine; C069715:trans-sialidase; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid