title: Structures of the Multidrug Transporter P-glycoprotein Reveal Asymmetric ATP Binding and the Mechanism of Polyspecificity.
abstract: P-glycoprotein (P-gp) is a polyspecific ATP-dependent transporter linked to multidrug resistance in cancer; it plays important roles in determining the pharmacokinetics of many drugs. Understanding the structural basis of P-gp, substrate polyspecificity has been hampered by its intrinsic flexibility, which is facilitated by a 75-residue linker that connects the two halves of P-gp. Here we constructed a mutant murine P-gp with a shortened linker to facilitate structural determination. Despite dramatic reduction in rhodamine 123 and calcein-AM transport, the linker-shortened mutant P-gp possesses basal ATPase activity and binds ATP only in its N-terminal nucleotide-binding domain. Nine independently determined structures of wild type, the linker mutant, and a methylated P-gp at up to 3.3 Å resolution display significant movements of individual transmembrane domain helices, which correlated with the opening and closing motion of the two halves of P-gp. The open-and-close motion alters the surface topology of P-gp within the drug-binding pocket, providing a mechanistic explanation for the polyspecificity of P-gp in substrate interactions.
authors.affiliation: From the Laboratory of Cell Biology, Center for Cancer Research, NCI.
authors.forename: Lothar
authors.initials: L
authors.lastname: Esser
authors.affiliation: From the Laboratory of Cell Biology, Center for Cancer Research, NCI.
authors.forename: Fei
authors.initials: F
authors.lastname: Zhou
authors.affiliation: From the Laboratory of Cell Biology, Center for Cancer Research, NCI.
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Pluchino
authors.affiliation: the Biotechnology Unit, NIDDK, and.
authors.forename: Joseph
authors.initials: J
authors.lastname: Shiloach
authors.affiliation: From the Laboratory of Cell Biology, Center for Cancer Research, NCI.
authors.forename: Jichun
authors.initials: J
authors.lastname: Ma
authors.affiliation: From the Laboratory of Cell Biology, Center for Cancer Research, NCI.
authors.forename: Wai-Kwan
authors.initials: WK
authors.lastname: Tang
authors.affiliation: From the Laboratory of Cell Biology, Center for Cancer Research, NCI.
authors.forename: Camilo
authors.initials: C
authors.lastname: Gutierrez
authors.affiliation: From the Laboratory of Cell Biology, Center for Cancer Research, NCI.
authors.forename: Alex
authors.initials: A
authors.lastname: Zhang
authors.affiliation: From the Laboratory of Cell Biology, Center for Cancer Research, NCI.
authors.forename: Suneet
authors.initials: S
authors.lastname: Shukla
authors.affiliation: From the Laboratory of Cell Biology, Center for Cancer Research, NCI.
authors.forename: James P
authors.initials: JP
authors.lastname: Madigan
authors.affiliation: the Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Tongqing
authors.initials: T
authors.lastname: Zhou
authors.affiliation: the Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Kwong
authors.affiliation: From the Laboratory of Cell Biology, Center for Cancer Research, NCI.
authors.forename: Suresh V
authors.initials: SV
authors.lastname: Ambudkar
authors.affiliation: From the Laboratory of Cell Biology, Center for Cancer Research, NCI.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Gottesman
authors.affiliation: From the Laboratory of Cell Biology, Center for Cancer Research, NCI, xiad@mail.nih.gov.
authors.forename: Di
authors.initials: D
authors.lastname: Xia
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019943:Amino Acid Substitution; D001665:Binding Sites; D001693:Biological Transport, Active / Q000502:physiology; D018360:Crystallography, X-Ray; D006367:HeLa Cells; D006801:Humans; D020125:Mutation, Missense; D020112:Rhodamine 123 / Q000737:chemistry* / Q000378:metabolism; D013379:Substrate Specificity / Q000502:physiology
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020112:Rhodamine 123
keywords: ABC transporter; ATP-binding; ATPase; P-glycoprotein; asymmetry; crystal structure; glycoprotein; multidrug transporter; polyspecificity; structure