title: A glycosyltransferase involved in biosynthesis of triglycosylated glycopeptidolipids in Mycobacterium smegmatis: impact on surface properties.
abstract: The cell envelope of mycobacteria is a complex structure that plays an important role in the interactions of the cell with its environment and in the protection against the antimicrobial activity of the immune system. Glycopeptidolipids (GPLs) are species- or type species-specific glycolipids that are present at the surface of a number of mycobacteria and that are characterized by a high variability in glycosylation patterns. These GPLs possess various biological activities that depend mostly on the sugars capping the core molecule. In Mycobacterium smegmatis, the GPL core can be substituted by either two or three deoxyhexoses. In this study, we show that Gtf3 is a glycosyltransferase responsible for the synthesis of the triglycosylated GPLs. Biochemical analysis of these molecules, with a combination of mass spectrometry and chemical degradation methods, has shown that they contain three deoxyhexose moieties. The presence of the triglycosylated GPLs is associated with cell surface modifications that lead to a decrease in sliding motility as well as a modification in cellular aggregation and colony appearance on Congo red. Phylogenetic analysis indicated that Gtf3 is a member of a yet-uncharacterized glycosyltransferase family conserved among the mycobacteria.
authors.affiliation: Inserm-UMR570, Faculté de Médecine Necker-Enfants Malades, 156 rue de Vaugirard, Paris Cedex 15, F-75730, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Deshayes
authors.forename: Françoise
authors.initials: F
authors.lastname: Laval
authors.forename: Henri
authors.initials: H
authors.lastname: Montrozier
authors.forename: Mamadou
authors.initials: M
authors.lastname: Daffé
authors.forename: Gilles
authors.initials: G
authors.lastname: Etienne
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Reyrat
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D006001:Glycoconjugates / Q000737:chemistry; D006017:Glycolipids / Q000096:biosynthesis* / Q000737:chemistry; D006020:Glycopeptides / Q000096:biosynthesis* / Q000737:chemistry; D006031:Glycosylation; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism*; D006601:Hexoses / Q000032:analysis / Q000302:isolation & purification; D013058:Mass Spectrometry; D009068:Movement; D020102:Mycobacterium smegmatis / Q000201:enzymology* / Q000378:metabolism / Q000502:physiology; D010802:Phylogeny; D013499:Surface Properties
chemical_list: D001426:Bacterial Proteins; D006001:Glycoconjugates; D006017:Glycolipids; D006020:Glycopeptides; D006601:Hexoses; C010762:peptidoglycolipids; D016695:Glycosyltransferases