title: Reconstitution of phospholipid flippase activity from E. coli inner membrane: a test of the protein translocon as a candidate flippase.
abstract: Phospholipid flipping in biogenic membranes is a key feature of membrane bilayer assembly. Flipping is facilitated by proteinaceous transporters (flippases) that do not need metabolic energy to function. No flippase has yet been identified. The architecture of the E. coli protein translocon suggests that it could account for the flippase activity in the bacterial inner membrane. To test this possibility, we used E. coli cells depleted of SecYE or YidC to assay flipping in proteoliposomes reconstituted from detergent extracts of their inner membranes. We conclude that the protein translocon contributes minimally, if at all, to phospholipid flippase activity in the inner membrane.
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, 53706-1569, USA.
authors.forename: William E
authors.initials: WE
authors.lastname: Watkins
authors.forename: Anant K
authors.initials: AK
authors.lastname: Menon
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D008051:Lipid Bilayers / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D026901:Membrane Transport Proteins; D010743:Phospholipids / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D000069816:SEC Translocation Channels
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D008051:Lipid Bilayers; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D010743:Phospholipids; D000069816:SEC Translocation Channels; C057841:SecY protein, E coli; C412443:YIDC protein, E coli