title: Investigating the function of the putative mycolic acid methyltransferase UmaA: divergence between the Mycobacterium smegmatis and Mycobacterium tuberculosis proteins.
abstract: Mycolic acids are major and specific lipid components of the cell envelope of mycobacteria that include the causative agents of tuberculosis and leprosy, Mycobacterium tuberculosis and Mycobacterium leprae, respectively. Subtle structural variations that are known to be crucial for both their virulence and the permeability of their cell envelope occur in mycolic acids. Among these are the introduction of cyclopropyl groups and methyl branches by mycolic acid S-adenosylmethionine-dependent methyltransferases (MA-MTs). While the functions of seven of the M. tuberculosis MA-MTs have been either established or strongly presumed nothing is known of the roles of the remaining umaA gene product and those of M. smegmatis MA-MTs. Mutants of the M. tuberculosis umaA gene and its putative M. smegmatis orthologue, MSMEG0913, were created. The lipid extracts of the resulting mutants were analyzed in detail using a combination of analytical techniques such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and proton nuclear magnetic resonance spectroscopy, and chemical degradation methods. The M. smegmatis mutants no longer synthesized subtypes of mycolates containing a methyl branch adjacent to either trans cyclopropyl group or trans double bond at the "proximal" position of both alpha- and epoxy-mycolates. Complementation with MSMEG0913, but not with umaA, fully restored the wild-type phenotype in M. smegmatis. Consistently, no modification was observed in the structures of mycolic acids produced by the M. tuberculosis umaA mutant. These data proved that despite their synteny and high similarity umaA and MSMEG0913 are not functionally orthologous.
authors.affiliation: Institut de Pharmacologie et Biologie Structurale (IPBS), Université Paul Sabatier (Toulouse III), 205 route de Narbonne, 31077 Toulouse Cedex, France; Department Mécanismes Moléculaires des Infections Mycobactériennes, Institut de Pharmacologie et Biologie Structurale (IPBS), Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5089), 205 route de Narbonne, 31077 Toulouse Cedex, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Laval
authors.affiliation: Department of Microbiology and Immunology, University of Melbourne, Royal Parade, Parkville, Victoria 3010, Australia.
authors.forename: Ruth
authors.initials: R
authors.lastname: Haites
authors.affiliation: Department of Pathology and Infectious Diseases, Royal Veterinary College, Royal College Street, London NW1 0TU, United Kingdom.
authors.forename: Farahnaz
authors.initials: F
authors.lastname: Movahedzadeh
authors.affiliation: Institut de Pharmacologie et Biologie Structurale (IPBS), Université Paul Sabatier (Toulouse III), 205 route de Narbonne, 31077 Toulouse Cedex, France; Department Mécanismes Moléculaires des Infections Mycobactériennes, Institut de Pharmacologie et Biologie Structurale (IPBS), Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5089), 205 route de Narbonne, 31077 Toulouse Cedex, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Lemassu
authors.affiliation: Department of Microbiology and Immunology, University of Melbourne, Royal Parade, Parkville, Victoria 3010, Australia.
authors.forename: Chinn Yi
authors.initials: CY
authors.lastname: Wong
authors.affiliation: Department of Pathology and Infectious Diseases, Royal Veterinary College, Royal College Street, London NW1 0TU, United Kingdom.
authors.forename: Neil
authors.initials: N
authors.lastname: Stoker
authors.affiliation: Department of Microbiology and Immunology, University of Melbourne, Royal Parade, Parkville, Victoria 3010, Australia.
authors.forename: Helen
authors.initials: H
authors.lastname: Billman-Jacobe
authors.affiliation: Institut de Pharmacologie et Biologie Structurale (IPBS), Université Paul Sabatier (Toulouse III), 205 route de Narbonne, 31077 Toulouse Cedex, France; Department Mécanismes Moléculaires des Infections Mycobactériennes, Institut de Pharmacologie et Biologie Structurale (IPBS), Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5089), 205 route de Narbonne, 31077 Toulouse Cedex, France. Electronic address: daffe@ipbs.fr.
authors.forename: Mamadou
authors.initials: M
authors.lastname: Daffé
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D004789:Enzyme Activation; D004852:Epoxy Compounds / Q000302:isolation & purification; D004952:Esters / Q000302:isolation & purification; D005816:Genetic Complementation Test; D009682:Magnetic Resonance Spectroscopy; D008780:Methyltransferases / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D020102:Mycobacterium smegmatis / Q000201:enzymology*; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D009171:Mycolic Acids / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D001426:Bacterial Proteins; D004852:Epoxy Compounds; D004952:Esters; D009171:Mycolic Acids; D008780:Methyltransferases