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Effect of lipid fluidity upon the activity and structure of the 39 kDa porin from Enterobacter cloacae 908S
Author(s) -
Ghosh Robin,
Aggeler Robert
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)80210-7
Subject(s) - porin , enterobacter cloacae , chemistry , lipid a , phospholipid , vesicle , biochemistry , hydrolysis , lipopolysaccharide , liposome , biophysics , bacterial outer membrane , enterobacteriaceae , membrane , biology , escherichia coli , gene , endocrinology
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 β‐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.