ARRANGEMENT OF PHOSPHATIDYLETHANOLAMINE MOLECULAR-SPECIES IN ESCHERICHIA-COLI MEMBRANES AND RECONSTITUTED LIPIDS AS DETERMINED BY DIMETHYL SUBERIMIDATE CROSS-LINKING OF NEAREST-NEIGHBOR LIPIDS
Mr. Roth et R. Welti, ARRANGEMENT OF PHOSPHATIDYLETHANOLAMINE MOLECULAR-SPECIES IN ESCHERICHIA-COLI MEMBRANES AND RECONSTITUTED LIPIDS AS DETERMINED BY DIMETHYL SUBERIMIDATE CROSS-LINKING OF NEAREST-NEIGHBOR LIPIDS, Biochimica et biophysica acta. Biomembranes, 1190(1), 1994, pp. 91-98
Dimethylsuberimidate cross-linking has been used to determine the arra
ngement of phosphatidylethanolamine (PE) molecular species in Escheric
hia coli membranes. No large deviations from random mixing were found
in wild-type strain AB1623, either in whole cells or in extracted lipi
ds which were reconstituted into multilamellar vesicles. These results
suggest, first, that there is little difference in the PE molecular s
pecies composition of the three lipid monolayers (the inner and outer
monolayers of the inner membrane and the inner monolayer of the outer
membrane) which contain significant amounts of PE. Secondly, the resul
ts suggest that the molecular species within each monolayer and in the
extracted lipids are arranged close to randomly with no tendency for
like molecular species to cluster. E. coli strain L8-2, which has a de
fect in beta-oxidation and a temperature-sensitive mutation in total f
atty acid synthesis, was grown on cis-vaccenate (cis-11,12-octadecenat
e) to enrich the cells in divaccenoyl PE. Again, in whole cells or in
lipids extracted from whole cells and reconstituted into multilamellar
vesicles, the species were close to randomly arranged. However, a con
sistent, slight tendency of divaccenoyl species to pair with like spec
ies as compared to pairing with the second most common species, vaccen
oyl, palmitoleoyl PE, was noted in both extracted lipids and in whole
cells.