Effect of lipid fluidity upon the activity and structure of the 39 kDa porin from Enterobacter cloacae 908S.
The 39 kDa porin from Enterobacter cloacae 908S was isolated in a lipopolysaccharide-free form using the non-ionic detergent, octylpentaoxyethylene, and reconstituted into vesicles of dimyristoylphosphatidylcholine (DMPC) and dioleoylphosphatidylcholine (DOPC), respectively. Porin activity, measured by the rate of hydrolysis of the lipid-impermeant beta-lactam cephazoline by entrapped lactamase, could be demonstrated for porin-DMPC but not for porin-DOPC vesicles, and for the former was significantly lower in the gel than in the liquid-crystalline phase. The fluorescence changes are thought to arise from lipid phase-induced structural/dynamic changes of the porin structure.
Ghosh
R
R
Pharmaceutical Research Department, F. Hoffmann-La Roche and Co. Ltd, Basel, Switzerland.
Aggeler
R
R
D001425:Bacterial Outer Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004134:Dimyristoylphosphatidylcholine; D004754:Enterobacter / Q000378:metabolism*; D004755:Enterobacteriaceae / Q000378:metabolism*; D007700:Kinetics; D008081:Liposomes; D008560:Membrane Fluidity; D008970:Molecular Weight; D010713:Phosphatidylcholines; D018272:Porins; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics; D001618:beta-Lactamases / Q000378:metabolism
D001425:Bacterial Outer Membrane Proteins; D008081:Liposomes; D010713:Phosphatidylcholines; D018272:Porins; D001618:beta-Lactamases; C017251:1,2-oleoylphosphatidylcholine; D004134:Dimyristoylphosphatidylcholine