title: Identification of a Novel Mycobacterial Arabinosyltransferase Activity Which Adds an Arabinosyl Residue to α-d-Mannosyl Residues.
abstract: The arabinosyltransferases responsible for the biosynthesis of the arabinan domains of two abundant heteropolysaccharides of the cell envelope of all mycobacterial species, lipoarabinomannan and arabinogalactan, are validated drug targets. Using a cell envelope preparation from Mycobacterium smegmatis as the enzyme source and di- and trimannoside synthetic acceptors, we uncovered a previously undetected arabinosyltransferase activity. Thin layer chromatography, GC/MS, and LC/MS/MS analyses of the major enzymatic product are consistent with the transfer of an arabinose residue to the 6 position of the terminal mannosyl residue at the nonreducing end of the acceptors. The newly identified enzymatic activity is resistant to ethambutol and could correspond to the priming arabinosyl transfer reaction that occurs during lipoarabinomannan biosynthesis.
authors.affiliation: Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University , Fort Collins, Colorado 80523-1682, United States.
authors.forename: Shiva Kumar
authors.initials: SK
authors.lastname: Angala
authors.affiliation: Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University , Fort Collins, Colorado 80523-1682, United States.
authors.forename: Michael R
authors.initials: MR
authors.lastname: McNeil
authors.affiliation: Alberta Glycomics Centre and Department of Chemistry, The University of Alberta , Edmonton, Alberta T6G 2G2, Canada.
authors.forename: Lu
authors.initials: L
authors.lastname: Zou
authors.affiliation: Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University , Fort Collins, Colorado 80523-1682, United States.
authors.forename: Avraham
authors.initials: A
authors.lastname: Liav
authors.affiliation: Alberta Glycomics Centre and Department of Chemistry, The University of Alberta , Edmonton, Alberta T6G 2G2, Canada.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Alberta Glycomics Centre and Department of Chemistry, The University of Alberta , Edmonton, Alberta T6G 2G2, Canada.
authors.forename: Todd L
authors.initials: TL
authors.lastname: Lowary
authors.affiliation: Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University , Fort Collins, Colorado 80523-1682, United States.
authors.forename: Mary
authors.initials: M
authors.lastname: Jackson
mesh_terms: D001089:Arabinose / Q000737:chemistry; D004187:Disaccharides / Q000737:chemistry; D057075:Enzyme Assays; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004977:Ethambutol / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000096:biosynthesis*; D020102:Mycobacterium smegmatis / Q000201:enzymology*; D009844:Oligosaccharides / Q000096:biosynthesis; D010430:Pentosyltransferases / Q000737:chemistry / Q000302:isolation & purification*; D012266:Ribose / Q000737:chemistry
chemical_list: D004187:Disaccharides; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D009844:Oligosaccharides; C050016:lipoarabinomannan; C000622568:mannopyranosyl-1-6-mannopyranosyl 1-octyl; D012266:Ribose; D004977:Ethambutol; D001089:Arabinose; D010430:Pentosyltransferases; C101967:arabinosyltransferase