Biophysical properties of a major membrane phospholipid, dielaidoylphosphatidylethanolamine, found in an Escherichia coli fatty acid auxotroph.

R. D. Yang, K. M. Patel, H. J. Pownall, R. D. Knapp, L. A. Sklar, R. B. Crawford, J. D. Morrisett

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

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).

Original languageEnglish (US)
Pages (from-to)8256-8262
Number of pages7
JournalJournal of Biological Chemistry
Volume254
Issue number17
StatePublished - Sep 10 1979

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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