title: Pleiotropic effect of AccD5 and AccE5 depletion in acyl-coenzyme A carboxylase activity and in lipid biosynthesis in mycobacteria.
abstract: Mycobacteria contain a large variety of fatty acids which are used for the biosynthesis of several complex cell wall lipids that have been implicated in the ability of the organism to resist host defenses. The building blocks for the biosynthesis of all these lipids are provided by a fairly complex set of acyl-CoA carboxylases (ACCases) whose subunit composition and roles within these organisms have not yet been clearly established. Previous biochemical and structural studies provided strong evidences that ACCase 5 from Mycobacterium tuberculosis is formed by the AccA3, AccD5 and AccE5 subunits and that this enzyme complex carboxylates acetyl-CoA and propionyl-CoA with a clear substrate preference for the latest. In this work we used a genetic approach to unambiguously demonstrate that the products of both accD5 and accE5 genes are essential for the viability of Mycobacterium smegmatis. By obtaining a conditional mutant on the accD5-accE5 operon, we also demonstrated that the main physiological role of this enzyme complex was to provide the substrates for fatty acid and mycolic acid biosynthesis. Furthermore, enzymatic and biochemical analysis of the conditional mutant provided strong evidences supporting the notion that AccD5 and/or AccE5 have an additional role in the carboxylation of long chain acyl-CoA prior to mycolic acid condensation. These studies represent a significant step towards a better understanding of the roles of ACCases in mycobacteria and confirm ACCase 5 as an interesting target for the development of new antimycobacterial drugs.
authors.affiliation: Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Bazet Lyonnet
authors.affiliation: Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Lautaro
authors.initials: L
authors.lastname: Diacovich
authors.affiliation: Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Matías
authors.initials: M
authors.lastname: Cabruja
authors.affiliation: CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), Département Tuberculose et Biologie des Infections, Toulouse, France; Université de Toulouse, UPS, IPBS, Toulouse, France.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Bardou
authors.affiliation: CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), Département Tuberculose et Biologie des Infections, Toulouse, France; Université de Toulouse, UPS, IPBS, Toulouse, France.
authors.forename: Annaïk
authors.initials: A
authors.lastname: Quémard
authors.affiliation: Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Gago
authors.affiliation: Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Hugo
authors.initials: H
authors.lastname: Gramajo
mesh_terms: D000105:Acetyl Coenzyme A; D000214:Acyl Coenzyme A; D000595:Amino Acid Sequence; D019735:Carbon-Carbon Ligases / Q000235:genetics*; D002473:Cell Wall / Q000235:genetics* / Q000378:metabolism; D005227:Fatty Acids / Q000235:genetics / Q000378:metabolism; D008055:Lipids / Q000096:biosynthesis*; D050155:Lipogenesis; D020102:Mycobacterium smegmatis / Q000235:genetics* / Q000378:metabolism; D009171:Mycolic Acids / Q000378:metabolism
chemical_list: D000214:Acyl Coenzyme A; D005227:Fatty Acids; D008055:Lipids; D009171:Mycolic Acids; D000105:Acetyl Coenzyme A; D019735:Carbon-Carbon Ligases; C018757:acyl-CoA carboxylase