title: A new subfamily of bacterial ABC-type transport systems catalyzing export of drugs and carbohydrates.
abstract: Sequence comparison studies revealed that the drug resistance transporter of Streptomyces peucetius (DrrAB) and two nodulation gene products (NodIJ) of Rhizobium leguminosarum are homologous to proteins encoded by three sets of genes that comprise capsular polysaccharide export systems in gram-negative bacteria: KpsTM of Escherichia coli, BexABC of Haemophilus influenzae, and CtrDCB of Neisseria meningitidis. These five systems comprise a new subfamily within the family of ATP binding cassette (ABC)-type transporters. We have termed this subfamily the ABC-2 subfamily. For three of the systems comprising this subfamily (Drr, Nod, and Kps) only one integral membrane constituent has been identified, whereas for the other two systems (Bex and Ctr) two dis-similar integral membrane constituents have been found. This observation suggests that the transmembrane channels of ABC-2-type transporters can be formed of homo- or heterooligomers as is true of several other classes of transport systems.
authors.affiliation: Department of Biology, University of California, San Diego, La Jolla 92093-0116.
authors.forename: J
authors.initials: J
authors.lastname: Reizer
authors.forename: A
authors.initials: A
authors.lastname: Reizer
authors.forename: M H
authors.initials: MH
authors.lastname: Saier
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001419:Bacteria / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D005075:Biological Evolution; D001693:Biological Transport, Active; D050260:Carbohydrate Metabolism; D002352:Carrier Proteins / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D002384:Catalysis; D004352:Drug Resistance, Microbial; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D026901:Membrane Transport Proteins; D000255:Adenosine Triphosphate