title: A small multidrug resistance-like transporter involved in the arabinosylation of arabinogalactan and lipoarabinomannan in mycobacteria.
abstract: The biosynthesis of the major cell envelope glycoconjugates of Mycobacterium tuberculosis is topologically split across the plasma membrane, yet nothing is known of the transporters required for the translocation of lipid-linked sugar donors and oligosaccharide intermediates from the cytoplasmic to the periplasmic side of the membrane in mycobacteria. One of the mechanisms used by prokaryotes to translocate lipid-linked phosphate sugars across the plasma membrane relies on translocases that share resemblance with small multidrug resistance transporters. The presence of an small multidrug resistance-like gene, Rv3789, located immediately upstream from dprE1/dprE2 responsible for the formation of decaprenyl-monophosphoryl-β-D-arabinose (DPA) in the genome of M. tuberculosis led us to investigate its potential involvement in the formation of the major arabinosylated glycopolymers, lipoarabinomannan (LAM) and arabinogalactan (AG). Disruption of the ortholog of Rv3789 in Mycobacterium smegmatis resulted in a reduction of the arabinose content of both AG and LAM that accompanied the accumulation of DPA in the mutant cells. Interestingly, AG and LAM synthesis was restored in the mutant not only upon expression of Rv3789 but also upon that of the undecaprenyl phosphate aminoarabinose flippase arnE/F genes from Escherichia coli. A bacterial two-hybrid system further indicated that Rv3789 interacts in vivo with the galactosyltransferase that initiates the elongation of the galactan domain of AG. Biochemical and genetic evidence is thus consistent with Rv3789 belonging to an AG biosynthetic complex, where its role is to reorient DPA to the periplasm, allowing this arabinose donor to then be used in the buildup of the arabinan domains of AG and LAM.
authors.affiliation: CNRS, Institut de Pharmacologie et de Biologie Structurale, Département Mécanismes Moléculaires des Infections Mycobactériennes, F-31077 Toulouse, France.
authors.forename: Gérald
authors.initials: G
authors.lastname: Larrouy-Maumus
authors.forename: Henrieta
authors.initials: H
authors.lastname: Škovierová
authors.forename: Rabeb
authors.initials: R
authors.lastname: Dhouib
authors.forename: Shiva Kumar
authors.initials: SK
authors.lastname: Angala
authors.forename: Sophie
authors.initials: S
authors.lastname: Zuberogoitia
authors.forename: Ha
authors.initials: H
authors.lastname: Pham
authors.forename: Anne Drumond
authors.initials: AD
authors.lastname: Villela
authors.forename: Katarina
authors.initials: K
authors.lastname: Mikušová
authors.forename: Audrey
authors.initials: A
authors.lastname: Noguera
authors.forename: Martine
authors.initials: M
authors.lastname: Gilleron
authors.forename: Lucia
authors.initials: L
authors.lastname: Valentínová
authors.forename: Jana
authors.initials: J
authors.lastname: Korduláková
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Brennan
authors.forename: Germain
authors.initials: G
authors.lastname: Puzo
authors.forename: Jérôme
authors.initials: J
authors.lastname: Nigou
authors.forename: Mary
authors.initials: M
authors.lastname: Jackson
mesh_terms: D001089:Arabinose / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D024901:Drug Resistance, Multiple, Bacterial / Q000502:physiology*; D005685:Galactans / Q000235:genetics / Q000378:metabolism*; D005816:Genetic Complementation Test; D006031:Glycosylation; D008070:Lipopolysaccharides / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D020102:Mycobacterium smegmatis / Q000235:genetics / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D005685:Galactans; D008070:Lipopolysaccharides; D026901:Membrane Transport Proteins; C050016:lipoarabinomannan; D001089:Arabinose; C005653:arabinogalactan