A description of the phospholipid arrangement intermediate to the humidity produced Lα and HII phases in dioleoylphosphatidylcholine and its modification by dioleoylphosphatidylethanolamine as studied by X-ray diffraction

Jeremy P. Bradshaw, Michael S. Edenborough, Philip J.H. Sizer, Anthony Watts

Research output: Contribution to journalArticle


X-ray diffraction from ordered multilayers has been used to study the structure of the lipid-water system in orientated multilayers of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) at 30°C as a function of water content. At high levels of water content the structure is lamellar (Lα), comprising equidistant lipid bilayers of constant thickness separated by layers of water. The low water content structure is a two-dimensional hexagonal array with narrow water channels (HII). X-ray scattering density profiles are derived for both structures. The presence of a stable intermediate rippled structure between the Lα and HII phases is demonstrated and a model is presented which involves a smooth structural transition between the two extremes described. The transition from Lα to HII phase is related to the bilayer thickness and not to any other variable parameter such as water content or composition. The effect of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) on the structure and phase transition characteristics of the system is reported.

Original languageEnglish
Pages (from-to)104-110
Number of pages7
JournalBBA - Biomembranes
Issue number1
Publication statusPublished - 11 Dec 1989


  • Dioleoylphosphatidylcholine bilayer
  • Hexagonal H phase
  • Lamellar phase
  • Rippled phase
  • Water/lipid system
  • X-ray diffraction

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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