title: Transbilayer movement of fluorescent phospholipid analogues in the cytoplasmic membrane of Escherichia coli.
abstract: We investigated the transmembrane movement of fluorescent labeled phospholipids in inverted inner membrane vesicles (IIMV) of Escherichia coli (E. coli) wild-type strain (MG1655), as well as in proteoliposomes reconstituted from detergent extracts of the IIMV. The transbilayer movement of 1-myristoyl-2-[6-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]caproyl]-sn-glycero-3-phosphoethanolamine (M-C6-NBD-PE) and -phosphocholine (M-C6-NBD-PC) was measured by a fluorescence stopped-flow back-exchange assay. Both analogues were rapidly translocated across the IIMV membrane, with half-times of <1 min (outward movement) and approximately 3 min (inward movement). No flip-flop was detected in protein-free liposomes, but in IIMV-derived proteoliposomes flip-flop of M-C6-NBD-PE occurred similarly to IIMV and could be largely eliminated by proteinase K treatment.
authors.affiliation: Mathematisch-Naturwissenschaftliche Fakultät I, Institut für Biologie/Biophysik, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany.
authors.forename: Janek
authors.initials: J
authors.lastname: Kubelt
authors.forename: Anant K
authors.initials: AK
authors.lastname: Menon
authors.forename: Peter
authors.initials: P
authors.lastname: Müller
authors.forename: Andreas
authors.initials: A
authors.lastname: Herrmann
mesh_terms: D009327:4-Chloro-7-nitrobenzofurazan / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism; D003593:Cytoplasm / Q000737:chemistry / Q000378:metabolism*; D003902:Detergents; D019286:Endopeptidase K / Q000378:metabolism; D004926:Escherichia coli / Q000737:chemistry / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000737:chemistry / Q000378:metabolism*; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D010713:Phosphatidylcholines / Q000737:chemistry / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000737:chemistry / Q000378:metabolism; D049294:Phospholipid Transfer Proteins; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism*; D011510:Proteolipids / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: D002352:Carrier Proteins; D003902:Detergents; D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D008565:Membrane Proteins; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D049294:Phospholipid Transfer Proteins; D010743:Phospholipids; D011510:Proteolipids; C020485:proteoliposomes; C052267:1,2-(palmitoyl-NBD-aminocaproyl)phosphatidylethanolamine; C044745:1-palmitoyl-2-(6-(N-(7-nitrobenz)-2-oxa-1,3-diazol-4-yl)aminocaproyl)phosphatidylcholine; D019286:Endopeptidase K; D009327:4-Chloro-7-nitrobenzofurazan