Resonance energy transfer involving tryptophan as a donor and anthrylvinyl-
labeled phosphatidylcholine (AV-PC), 3-methoxybenzanthrone (MBA) and 8-anil
ino-1-naphthalene sulfonic acid (ANS) as acceptors has been examined to obt
ain information on the structure of peptide-lipid systems consisting of 18A
or Ac-18A-NH2 peptides and large unilamellar phosphatidylcholine vesicles.
The lower and upper limits for the tryptophan distance from the bilayer mi
dplane have been assessed in terms of the models of energy transfer in two-
dimensional systems, taking into account orientational effects. Evidence fo
r the existence of preferential orientations of Ac-18A-NH2 with respect to
the lipid-water interface has been obtained. (C) 2001 Elsevier Science B.V.
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