INVESTIGADORES
ANTOLLINI Silvia Susana
artículos
Título:
Unique effects of different fatty acid species on the physical properties of the torpedo acetylcholine receptor membrane
Autor/es:
ANTOLLINI, SILVIA SUSANA; BARRANTES, FRANCISCO JOSÉ
Revista:
JOURNAL OF BIOLOGICAL CHEMISTRY
Editorial:
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Referencias:
Lugar: Am Soc for Bioch and Mol Biol; Año: 2002 vol. 277 p. 1249 - 1254
ISSN:
0021-9258
Resumen:
To study the effects produced by free fatty acids (FFA)
on the biophysical properties of Torpedo marmorata
nicotinic acetylcholine receptor-rich native membranes
and to investigate the topology of their binding site(s),
fluorescence measurements were carried out using the
fluorescent probe Laurdan (6-dodecanoyl-2-(dimethylamino)
naphthalene) and ADIFAB, an Acrylodan-derivatized
intestinal fatty acid-binding protein. The generalized
polarization (GP) of the former probe was used to
learn about the physical state of the membrane upon
FFA binding. Saturated FFA induced a slight increase in
GP, whereas cis-unsaturated fatty acids decreased GP.
Double bond isomerism could also be distinguished;
oleic acid (18:1cis) induced a net disordering effect,
whereas elaidic acid (18:1trans) produced no changes in
GP. The changes in the efficiency of the Forster energy
transfer from the protein to Laurdan brought about by
addition of FFA, together with the distances involved in
this process, indicate that all FFA studied share a common
site at the lipid-protein interface. However, despite
being located at the same site, each class of FFA differs
in its effect on the physical properties of the membrane.
These data lead us to suggest that it is the direct action
of FFA at the lipid-protein interface, displacing essential
lipids from their sites rather than changes in bulk
properties such as membrane fluidity that accounts for
the effect of FFA on the acetylcholine receptor
membrane.