title: Projection structure of P-glycoprotein by electron microscopy. Evidence for a closed conformation of the nucleotide binding domains.
abstract: The structure of P-glycoprotein (Pgp) from mouse has been studied by electron microscopy and image analysis. Two-dimensional crystals of Pgp in a lipid bilayer were generated by reconstituting pure, detergent-solubilized protein containing a C-terminal six-histidine tag using the lipid monolayer technique. The crystals belong to plane group P1 with a = b = 104 +/- 2 A and gamma = 90 +/- 4 degrees. The projection structure of Pgp calculated at a resolution of 22 A shows two closely interacting protein domains that can be interpreted as the N- and C-terminal halves of the protein. The projection structure of Pgp is consistent with the recently published x-ray structure of MsbA, a lipid A flippase from Escherichia coli with high sequence homology to Pgp but only when the two MsbA subunits are rotated to bring their nucleotide binding domains together.
authors.affiliation: University of California, Riverside, Department of Biochemistry, Riverside, California 92521, USA.
authors.forename: Jyh-Yeuan
authors.initials: JY
authors.lastname: Lee
authors.forename: Ina L
authors.initials: IL
authors.lastname: Urbatsch
authors.forename: Alan E
authors.initials: AE
authors.lastname: Senior
authors.forename: Stephan
authors.initials: S
authors.lastname: Wilkens
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000737:chemistry*; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D003460:Crystallization; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000737:chemistry / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000378:metabolism; D008051:Lipid Bilayers; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D008854:Microscopy, Electron; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; C050021:BtuC peptide, E coli; C050022:BtuD peptide, E coli; D029968:Escherichia coli Proteins; D008051:Lipid Bilayers; D008565:Membrane Proteins; C079726:MsbA protein, Bacteria