Labelling of the Subunits of the Mitochondrial Adenosine Triphosphatase Complex in Contact with the Lipid Bilayer

Effect of pH on the interaction of botulinum neurotoxins A, B and E with liposomes

“…We have shown that PC I does indeed behave as a phospholipid and does not label from the water phase (Bisson et al, 1979(Bisson et al, , 1982Montecucco etal., 1980Montecucco etal., , 1983Montecucco etal., , 1985Hoppe etal., 1983). Moreover, in several cases we could also show that the fatty acid chain of PC II does not appreciably kink to the membrane surface (Montecucco et al, 1980(Montecucco et al, , 1983Tomasi & Montecucco, 1981;Giraudat et al, 1985;Ribi et al, 1988). In addition, superimposable results were obtained here when water-soluble quenchers of the photogenerated intermediates were used.…”

Membrane Topology of ATP Synthase from Bovine Heart Mitochondira and Escherichia coli

“…All operations involving the photoreactive lipids were performed under red safety light. Vesicles of egg phosphatidylcholine or soya-bean lipids were prepared by ultrasonic dispersion and incubated with the proteins as before [8,19]. Lipid-protein samples were irradiated (10min at 0 'C with a 100 W ultraviolet lamp, Ultraviolet Products, S. Gabriel, CA) and recovered by centrifugation on a 10 % sucrose gradient.…”

“…15% sucrose was included in the 5% polyacrylamide stacking gel and the running gel contained a 0-24% linear sucrose gradient. Gels were stained with Coomassie Blue and the associated radioactivity was determined either by gel slicing and counting as before [19] or by fluorography according to Bonner and Laskey [25]. Carbonic anhydrase, cytochrome c, bovine pancreas ribonuclease, trypsin inhibitor, myoglobin, insulin, melittin and the E. coli ATP synthetase ( M , as in [15]) were used as molecular weight standards.…”

“…To obtain more information on this point in a previous study we have used the hydrophobic photolabelling technique [19]. This approach allows the specific labelling and hence the identification of the polypeptide chains interacting directly with the phospholipid analogues .…”

Labelling of the hydrophobic domain of the Na+,K+‐ATPase

“…On illumination the photoactivatable nitroarylazido group is converted to a reactive nitrene intermediate which reacts with neighbouring molecules, thereby labelling them radioactively. These probes have been shown to label specifically those hydrophobic domains of several integral membrane proteins exposed to lipids [7][8][9]13,19].…”