A subtransition in a phospholipid with a net charge, dipalmitoylphosphatidylglycerol.

Journal Article (Journal Article)

Suspensions of dipalmitoylphosphatidylglycerol (DPPG) have been analyzed by differential scanning calorimetry, equilibrium and differential scanning dilatometry, and X-ray diffraction techniques. After the DPPG suspensions are stored several days at 2 degrees C, a new phase transition is observed at a lower temperature than either the main transition or the pretransition. This subtransition has an enthalpy of about 6 kcal/mol and occurs at about 20 degrees C, the exact temperature depending on the buffer used. The lipid partial specific volume increases by 0.035 mL/g upon warming through the subtransition. X-ray diffraction patterns from suspensions in the subgel phase contain orders of a lamellar repeat and several additional sharp and broad wide-angle reflections between 8 and 2 A. As the water content in the specimen is reduced, the lamellar repeat period decreases, whereas the spacings and intensities of these additional wide-angle reflections are unchanged. These data indicate that on incubation at 2 degrees C the lipid molecules crystallize in the plane of each bilayer. X-ray experiments also show that this subgel phase converts to the normal L beta' gel phase above the subtransition.

Full Text

Duke Authors

Cited Authors

  • Wilkinson, DA; McIntosh, TJ

Published Date

  • January 28, 1986

Published In

Volume / Issue

  • 25 / 2

Start / End Page

  • 295 - 298

PubMed ID

  • 3954999

International Standard Serial Number (ISSN)

  • 0006-2960

Digital Object Identifier (DOI)

  • 10.1021/bi00350a002


  • eng

Conference Location

  • United States