title: Membrane topology of the DrrB protein of the doxorubicin transporter of Streptomyces peucetius.
abstract: Daunorubicin and doxorubicin, two commonly used anticancer agents, are produced by the soil bacterium Streptomyces peucetius. Self-resistance to these antibiotics in S. peucetius is conferred by the drrAB locus that codes for two proteins, DrrA and DrrB. DrrA is an ATP-binding protein. It belongs to the ABC family of transporters and shares sequence and functional similarities with P-glycoprotein of cancer cells. DrrB is an integral membrane protein that might function as a transporter for the efflux of daunorubicin and doxorubicin. Together, DrrA and DrrB are believed to form an ATP-driven pump for the efflux of these drugs. The drrAB locus has been cloned, and the two proteins have been expressed in a functional form in Escherichia coli. A topological analysis of the DrrB protein was performed using gene fusion methodology. Random and site-directed fusions of the drrB gene to lacZ, phoA, or gfp reporter genes were created. Based on the fusion data, a topological model of the DrrB protein is proposed in which the protein has eight membrane-spanning domains with both the N terminus and the C terminus in the cytoplasm.
authors.affiliation: Department of Biology, Georgia State University, Atlanta, Georgia 30303, USA.
authors.forename: Suvarna M
authors.initials: SM
authors.lastname: Gandlur
authors.forename: Ling
authors.initials: L
authors.lastname: Wei
authors.forename: Jeoffery
authors.initials: J
authors.lastname: Levine
authors.forename: Jack
authors.initials: J
authors.lastname: Russell
authors.forename: Parjit
authors.initials: P
authors.lastname: Kaur
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D000595:Amino Acid Sequence; D019677:Artificial Gene Fusion / Q000379:methods; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D001692:Biological Transport; D004317:Doxorubicin / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D016297:Mutagenesis, Site-Directed; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D013302:Streptomyces / Q000235:genetics / Q000378:metabolism*; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D004317:Doxorubicin; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D011993:Recombinant Fusion Proteins; D001616:beta-Galactosidase; C104038:DrrB protein, Streptomyces peucetius