title: Two membrane proteins from Bifidobacterium breve UCC2003 constitute an ABC-type multidrug transporter.
abstract: Intrinsic resistance to drugs is one of the main determining factors in bacterial survival in the intestinal ecosystem. This is mediated by, among others, multidrug resistance (MDR) transporters, membrane proteins which extrude noxious compounds with very different chemical structures and cellular targets. Two genes from Bifidobacterium breve encoding hypothetical membrane proteins with a high homology with members of the ATP-binding cassette (ABC) family of multidrug efflux transporters, were expressed separately and jointly in Lactococcus lactis. Cells co-expressing both proteins exhibited enhanced resistance levels to the antimicrobials nisin and polymyxin B. Furthermore, the drug extrusion activity in membrane vesicles was increased when both proteins were co-expressed, compared to membranes in which the proteins were produced independently. Both proteins were co-purified from the membrane as a stable complex in a 1:1 ratio. This is believed to be the first study of a functional ABC-type multidrug transporter in Bifidobacterium and contributes to our understanding of the molecular mechanisms underlying the capacity of intestinal bacteria to tolerate cytotoxic compounds.
authors.affiliation: Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (CSIC), Ctra Infiesto s/n, 33300, Villaviciosa, Asturias, Spain.
authors.forename: Abelardo
authors.initials: A
authors.lastname: Margolles
authors.affiliation: Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (CSIC), Ctra Infiesto s/n, 33300, Villaviciosa, Asturias, Spain.
authors.forename: Ana Belén
authors.initials: AB
authors.lastname: Flórez
authors.affiliation: Department of Microbiology and Alimentary Pharmabiotic Centre, University College Cork, Western Road, Cork, Ireland.|Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (CSIC), Ctra Infiesto s/n, 33300, Villaviciosa, Asturias, Spain.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Moreno
authors.affiliation: Department of Microbiology and Alimentary Pharmabiotic Centre, University College Cork, Western Road, Cork, Ireland.
authors.forename: Douwe
authors.initials: D
authors.lastname: van Sinderen
authors.affiliation: Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (CSIC), Ctra Infiesto s/n, 33300, Villaviciosa, Asturias, Spain.
authors.forename: Clara G
authors.initials: CG
authors.lastname: de Los Reyes-Gavilán
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001562:Benzimidazoles / Q000378:metabolism; D001644:Bifidobacterium / Q000737:chemistry / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D019281:Dimerization; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D015870:Gene Expression; D013294:Lactococcus lactis / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D009561:Nisin / Q000494:pharmacology; D010802:Phylogeny; D011112:Polymyxin B / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D022161:Transport Vesicles / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001562:Benzimidazoles; D004269:DNA, Bacterial; D008565:Membrane Proteins; D009561:Nisin; D011112:Polymyxin B; C017807:bisbenzimide ethoxide trihydrochloride