Characterization of three glycosyltransferases involved in the biosynthesis of the phenolic glycolipid antigens from the Mycobacterium tuberculosis complex.
Mycobacterium tuberculosis and Mycobacterium leprae, the two main mycobacterial pathogens in humans, produce highly specific long chain beta-diols, the dimycocerosates of phthiocerol, and structurally related phenolic glycolipid (PGL) antigens, which are important virulence factors. In addition, M. tuberculosis also secretes glycosylated p-hydroxybenzoic acid methyl esters (p-HBAD) that contain the same carbohydrate moiety as the species-specific PGL of M. tuberculosis (PGL-tb). The genes involved in the biosynthesis of these compounds in M. tuberculosis are grouped on a 70-kilobase chromosomal fragment containing three genes encoding putative glycosyltransferases: Rv2957, Rv2958c, and Rv2962c. To determine the functions of these genes, three recombinant M. tuberculosis strains, in which these genes were individually inactivated, were constructed and biochemically characterized. Our results demonstrated that (i) the biosynthesis of PGL-tb and p-HBAD involves common enzymatic steps, (ii) the Rv2957, Rv2958c, and Rv2962c genes are involved in the formation of the glycosyl moiety of the two classes of molecules, and (iii) the product of Rv2962c catalyzes the transfer of a rhamnosyl residue onto p-hydroxybenzoic acid ethyl ester or phenolphthiocerol dimycocerosates, whereas the products of Rv2958c and Rv2957 add a second rhamnosyl unit and a fucosyl residue to form the species-specific triglycosyl appendage of PGL-tb and p-HBAD. The recombinant strains produced provide the tools to study the role of the carbohydrate domain of PGL-tb and p-HBAD in M. tuberculosis pathogenesis.
Département "Mécanismes Moléculaires des Infections Mycobactériennes," Institut de Pharmacologie et Biologie Structurale, CNRS and Université Paul Sabatier (Unité Mixte de Recherche 5089), 205 route de Narbonne, 31077 Toulouse Cedex, France.
Esther
E
Pérez
Patricia
P
Constant
Anne
A
Lemassu
Françoise
F
Laval
Mamadou
M
Daffé
Christophe
C
Guilhot
D000941:Antigens / Q000737:chemistry; D000942:Antigens, Bacterial / Q000737:chemistry*; D002240:Carbohydrate Sequence; D002384:Catalysis; D002849:Chromatography, Gas; D002855:Chromatography, Thin Layer; D002875:Chromosomes / Q000648:ultrastructure; D003470:Culture Media / Q000494:pharmacology; D005816:Genetic Complementation Test; D006017:Glycolipids / Q000737:chemistry*; D006031:Glycosylation; D016695:Glycosyltransferases / Q000737:chemistry*; D007834:Lasers; D008055:Lipids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008956:Models, Chemical; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D009163:Mycobacterium bovis / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000737:chemistry*; D010226:Parabens / Q000737:chemistry; D019800:Phenol / Q000737:chemistry*; D010957:Plasmids / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D012210:Rhamnose / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014466:Ultraviolet Rays
D000941:Antigens; D000942:Antigens, Bacterial; D003470:Culture Media; D006017:Glycolipids; D008055:Lipids; D010226:Parabens; D011994:Recombinant Proteins; D019800:Phenol; C015358:methylparaben; D016695:Glycosyltransferases; C493167:Rv2957 protein, Mycobacterium tuberculosis; C493168:Rv2958c protein, Mycobacterium tuberculosis; C493169:Rv2962c protein, Mycobacterium tuberculosis; D012210:Rhamnose