X-Message-Number: 12708
Date: Thu, 4 Nov 1999 05:15:09 -0800 (PST)
From: Doug Skrecky <>
Subject: more on DMSO and membranes

Authors
  Gordeliy VI.  Kiselev MA.  Lesieur P.  Pole AV.  Teixeira J.
Institution
  IBI-2, Structural Biology, Forschungszentrum Julich, D-52425 Julich, Germany.
  
Title
  Lipid membrane structure
  and interactions in dimethyl sulfoxide/water mixtures.
Source
  Biophysical Journal.  75(5):2343-51, 1998 Nov.
Abstract
  In this paper we have investigated via x-ray diffraction the influence of
  dimethyl sulfoxide (DMSO), known for its biological and therapeutic
  properties, on the structure of lipid
  membranes of dipalmitoylphosphatidylcholine (DPPC) in excess
  of the solvent (DMSO/water) at mole DMSO fractions XDMSO in (0.1) and under
  equilibrium conditions. At small XDMSO </= 0.133 the repeat distance d is
  reduced remarkably, whereas wide-angle x-ray diffraction pattern remains
  almost unchanged with the increase in XDMSO. It agrees well with previous
  study (Yu and Quinn, 1995). At 0.133 < XDMSO < 0.3 the repeat period d
  reduces slowly; however, an orthorombic in-plane lattice of hydrocarbon
  chains transfers to a disordered quasihexagonal lattice. The increase in
  XDMSO from 0.3 up to approximately 0.9 leaves d almost unchanged, whereas it
  leads to less disordered packing of hydrocarbon chains. At XDMSO
  approximately 0.9, Lbeta' phase transfers into interdigitated phase. The
  chain-melting phase transition temperature of DPPC membranes
  increases by several degrees with the increase of DMSO concentration. It
  points to a strong concentration-dependent solvation of
  membrane surface by DMSO. Thus DMSO strongly interacts with
  the membrane surface, probably displacing water and
  modifying the structure of the lipid
  bilayer. It appears to determine some of the properties of DMSO as a
  biologically and therapeutically active substance.

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