Genetic basis for the biosynthesis of methylglucose lipopolysaccharides in Mycobacterium tuberculosis.
Mycobacteria produce two unusual polymethylated polysaccharides, the 6-O-methylglucosyl-containing lipopolysaccharides (MGLP) and the 3-O-methylmannose polysaccharides, which have been shown to regulate fatty acid biosynthesis in vitro. A cluster of genes dedicated to the synthesis of MGLP was identified in Mycobacterium tuberculosis and Mycobacterium smegmatis. Overexpression of the putative glycosyltransferase gene Rv3032 in M. smegmatis greatly stimulated MGLP production, whereas the targeted disruption of Rv3032 in M. tuberculosis and that of the putative methyltransferase gene MSMEG2349 in M. smegmatis resulted in a dramatic reduction in the amounts of MGLP synthesized and in the accumulation of precursors of these molecules. Disruption of Rv3032 also led to a significant decrease in the glycogen content of the tubercle bacillus, indicating that the product of this gene is likely to be involved in the elongation of more than one alpha-(1-->4)-glucan in this bacterium. Results thus suggest that Rv3032 encodes the alpha-(1-->4)-glucosyltransferase responsible for the elongation of MGLP, whereas MSMEG2349 encodes the O-methyltransferase required for the 6-O-methylation of these compounds.
Stadthagen
Gustavo
G
UnitédeGénétique Mycobactérienne Institut Pasteur, 75015 Paris, France.
Sambou
Tounkang
T
Département Mécanismes Moléculaires des Infections Mycobactériennes, Institut de Pharmacologie et de Biologie Structurale, CNRS, 31077 Toulouse, France.
Guerin
Marcelo
M
Unité de Biochimie Structurale, Institut Pasteur, 75015 Paris, France and the.
Barilone
Nathalie
N
UnitédeGénétique Mycobactérienne Institut Pasteur, 75015 Paris, France.
Boudou
Frédéric
F
UnitédeGénétique Mycobactérienne Institut Pasteur, 75015 Paris, France.
Korduláková
Jana
J
UnitédeGénétique Mycobactérienne Institut Pasteur, 75015 Paris, France.
Charles
Patricia
P
UnitédeGénétique Mycobactérienne Institut Pasteur, 75015 Paris, France.
Alzari
Pedro M
PM
Unité de Biochimie Structurale, Institut Pasteur, 75015 Paris, France and the.
Lemassu
Anne
A
Département Mécanismes Moléculaires des Infections Mycobactériennes, Institut de Pharmacologie et de Biologie Structurale, CNRS, 31077 Toulouse, France.
Daffé
Mamadou
M
Département Mécanismes Moléculaires des Infections Mycobactériennes, Institut de Pharmacologie et de Biologie Structurale, CNRS, 31077 Toulouse, France.
Puzo
Germain
G
Département Mécanismes Moléculaires des Infections Mycobactériennes, Institut de Pharmacologie et de Biologie Structurale, CNRS, 31077 Toulouse, France.
Gicquel
Brigitte
B
UnitédeGénétique Mycobactérienne Institut Pasteur, 75015 Paris, France.
Rivière
Michel
M
Département Mécanismes Moléculaires des Infections Mycobactériennes, Institut de Pharmacologie et de Biologie Structurale, CNRS, 31077 Toulouse, France.
Jackson
Mary
M
UnitédeGénétique Mycobactérienne Institut Pasteur, 75015 Paris, France. Electronic address: Mary.Jackson@colostate.edu.
D006003:Glycogen / Q000032:analysis; D016695:Glycosyltransferases / Q000235:genetics / Q000502:physiology; D008070:Lipopolysaccharides / Q000096:biosynthesis*; D008757:Methylglucosides / Q000032:analysis*; D005810:Multigene Family; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D008070:Lipopolysaccharides; D008757:Methylglucosides; C033884:6-O-methylglucose; D006003:Glycogen; D016695:Glycosyltransferases