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Dielaidoylphosphatidylethanolamine, a principal lipid component of membranes of Escherichia coli fatty acid auxotrophs enriched in elaidic acid, has been studied by paramagnetic resonance, fluorescence, and calorimetric methods. EPR measurements with perdeutero-di-tert-butylnitroxide and 2,2,6,6-tetramethyl piperidine-1-oxyl indicate that, when dispersed in aqueous media, this phospholipid undergoes an abrupt order leads to disorder transition at 37.5 degrees C and 36.5 C, respectively. A similar transition temperature is suggested by experiments with 9-doxyl-dimyristoylphosphatidylethanolamine (DEPE). cis- and trans-Parinaric-acid fluorescence polarization measurements indicate that the midpoint of this transition occurs at 34.0 degrees C and 35.5 degrees C, respectively. Differential scanning calorimetry of DEPE revealed a single, sharp endotherm at 38.5 degrees C with increasing temperature; two exotherms of similar magnitude were observed at 36.5 degrees C and 34.5 degrees C upon cooling. This double transition was not observed by any of the other methods. From these results we conclude that the major structural transition at 30-31 degrees C observed previously with 5-, 12-, and 16-doxyl stearate in intact E. coli membranes is due to the DEPE present (Morrisett, J.D., Pownall, H.J., Plumlee, R.T., Smith, L.C., Zehner, Z.E., Esfahani, M., and Wakil, S.J. (1975) J. Biol. Chem. 250, 6969-6976).
R D Yang, and
K M Patel, and
H J Pownall, and
R D Knapp, and
L A Sklar, and
R B Crawford, and
J D Morrisett
May 1977,
Biochimica et biophysica acta,
R D Yang, and
K M Patel, and
H J Pownall, and
R D Knapp, and
L A Sklar, and
R B Crawford, and
J D Morrisett
May 1968,
Journal of bacteriology,
R D Yang, and
K M Patel, and
H J Pownall, and
R D Knapp, and
L A Sklar, and
R B Crawford, and
J D Morrisett
January 1974,
Methods in enzymology,
R D Yang, and
K M Patel, and
H J Pownall, and
R D Knapp, and
L A Sklar, and
R B Crawford, and
J D Morrisett
December 1972,
Journal of bacteriology,
R D Yang, and
K M Patel, and
H J Pownall, and
R D Knapp, and
L A Sklar, and
R B Crawford, and
J D Morrisett
June 1975,
The Journal of biological chemistry,
R D Yang, and
K M Patel, and
H J Pownall, and
R D Knapp, and
L A Sklar, and
R B Crawford, and
J D Morrisett
August 1988,
Applied and environmental microbiology,
R D Yang, and
K M Patel, and
H J Pownall, and
R D Knapp, and
L A Sklar, and
R B Crawford, and
J D Morrisett
December 1973,
Journal of bacteriology,
R D Yang, and
K M Patel, and
H J Pownall, and
R D Knapp, and
L A Sklar, and
R B Crawford, and
J D Morrisett
December 1981,
Canadian journal of microbiology,
R D Yang, and
K M Patel, and
H J Pownall, and
R D Knapp, and
L A Sklar, and
R B Crawford, and
J D Morrisett
September 1970,
Biochemistry,
R D Yang, and
K M Patel, and
H J Pownall, and
R D Knapp, and
L A Sklar, and
R B Crawford, and
J D Morrisett
November 1969,
Proceedings of the National Academy of Sciences of the United States of America,
