title: Cryo-EM Analysis of the Conformational Landscape of Human P-glycoprotein (ABCB1) During its Catalytic Cycle.
abstract: The multidrug transporter P-glycoprotein (P-gp, ABCB1) is an ATP-dependent pump that mediates the efflux of structurally diverse drugs and xenobiotics across cell membranes, affecting drug pharmacokinetics and contributing to the development of multidrug resistance. Structural information about the conformational changes in human P-gp during the ATP hydrolysis cycle has not been directly demonstrated, although mechanistic information has been inferred from biochemical and biophysical studies conducted with P-gp and its orthologs, or from structures of other ATP-binding cassette transporters. Using single-particle cryo-electron microscopy, we report the surprising discovery that, in the absence of the transport substrate and nucleotides, human P-gp can exist in both open [nucleotide binding domains (NBDs) apart; inward-facing] and closed (NBDs close; outward-facing) conformations. We also probe conformational states of human P-gp during the catalytic cycle, and demonstrate that, following ATP hydrolysis, P-gp transitions through a complete closed conformation to a complete open conformation in the presence of ADP.
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Gabriel A
authors.initials: GA
authors.lastname: Frank
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Suneet
authors.initials: S
authors.lastname: Shukla
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Prashant
authors.initials: P
authors.lastname: Rao
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Mario J
authors.initials: MJ
authors.lastname: Borgnia
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Alberto
authors.initials: A
authors.lastname: Bartesaghi
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Alan
authors.initials: A
authors.lastname: Merk
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Aerfa
authors.initials: A
authors.lastname: Mobin
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Lothar
authors.initials: L
authors.lastname: Esser
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Lesley A
authors.initials: LA
authors.lastname: Earl
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Gottesman
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Di
authors.initials: D
authors.lastname: Xia
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland ambudkar@helix.nih.gov ss1@nih.gov.
authors.forename: Suresh V
authors.initials: SV
authors.lastname: Ambudkar
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland ambudkar@helix.nih.gov ss1@nih.gov.
authors.forename: Sriram
authors.initials: S
authors.lastname: Subramaniam
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000737:chemistry / Q000648:ultrastructure; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D055162:Biocatalysis; D020285:Cryoelectron Microscopy; D018360:Crystallography, X-Ray; D006801:Humans; D006868:Hydrolysis; D008954:Models, Biological; D011487:Protein Conformation
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate