title: Structural elucidation of novel methylglucose-containing polysaccharides from Mycobacterium xenopi.
abstract: The structures of methylglucose-containing polysaccharides (MeGlc PS) from Mycobacterium xenopi were investigated using high-pH anion-exchange chromatography and liquid secondary-ion mass spectrometry. We report the structure of two novel MeGlc PS, referred to as A and B. MeGlc PS A is composed of 16 D-glucopyranose residues, 11 of which are methylated, and MeGlc PS B contains 15 D-glucopyranose residues, 10 of which are methylated. The main structural feature of both MeGlc PS A and B, compared to the previously described structures, is the absence of the tetrasaccharide non-reducing end 3-O-Me-D-Glcp-[alpha(1-->4)-D-Glcp]3. The MeGlc PS A structure is similar to the synthetic polysaccharide [Saïer, M. H. & Ballou, C. E. (1968) J. Biol. Chem. 243, 992-1005], having a lower affinity for fatty acids than the MeGlc PS of Mycobacterium smegmatis [Kiho, T. & Ballou, C. E. (1988) Biochemistry 27, 5824-5828]. Thus, the occurrence of MeGlc PS A and the consequences on the regulation of fatty acid synthetase I activity involved in the biosynthesis of fatty acids, precursors of mycolic acid biosynthesis, is discussed.
authors.affiliation: Laboratoire de Pharmacologie et de Toxicologie Fondamentales du Centre National de la Recherche Scientifique, Toulouse, France.
authors.forename: G
authors.initials: G
authors.lastname: Tuffal
authors.forename: C
authors.initials: C
authors.lastname: Ponthus
authors.forename: C
authors.initials: C
authors.lastname: Picard
authors.forename: M
authors.initials: M
authors.lastname: Rivière
authors.forename: G
authors.initials: G
authors.lastname: Puzo
mesh_terms: D019325:3-O-Methylglucose; D002240:Carbohydrate Sequence; D002852:Chromatography, Ion Exchange; D064429:Fatty Acid Synthases / Q000378:metabolism; D005227:Fatty Acids / Q000096:biosynthesis / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry; D008745:Methylation; D008757:Methylglucosides / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009171:Mycolic Acids / Q000378:metabolism; D009170:Nontuberculous Mycobacteria / Q000737:chemistry* / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000737:chemistry* / Q000378:metabolism
chemical_list: D005227:Fatty Acids; D008757:Methylglucosides; D009171:Mycolic Acids; D011135:Polysaccharides, Bacterial; D019325:3-O-Methylglucose; D064429:Fatty Acid Synthases