Transbilayer movement of fluorescent phospholipid analogues in the cytoplasmic membrane of Escherichia coli.
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.
Kubelt
Janek
J
Mathematisch-Naturwissenschaftliche Fakultät I, Institut für Biologie/Biophysik, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany.
Menon
Anant K
AK
Müller
Peter
P
Herrmann
Andreas
A
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
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