Membrane structure and dynamics by 2H- and 31P-NMR. Effects of amphipatic peptidic toxins on phospholipid and biological membranes

Biochimie
Erick J DufourcJ Dufourcq

Abstract

The actions of bee venom melittin and delta-lysin from Staphylococcus aureus on membranes have been monitored by solid-state deuterium and phosphorus NMR and shown to differ depending on temperature and on the lipid-to-peptide molar ratio Ri. In the gel phase of phosphatidylcholine model membranes, for lipid-to-peptide ratios Ri greater than 15, melittin induces isotropic lines interpreted as reflecting the presence of small discoidal structures, whereas delta-lysin does not. These small objects are metastable, that is, within a time-scale of hours they return to large lipid bilayers. The kinetics of this process depend on the lecithin chain length. In the fluid phases, at temperatures greater than that of the gel-to-fluid transition Tc, analysis of the quadruplar splittings in terms of chain ordering indicates that both melittin and delta-lysin similarly disorder the membrane. At temperatures above but close to Tc, melittin preferentially orders the center of the bilayer, while delta-lysin promotes ordering throughout the entire bilayer thickness. These effects are interpreted as reflecting different locations of the peptides with respect to the membrane surface. The addition of greater amounts of toxins, Ri = 4, on phosphatid...Continue Reading

Citations

Jul 2, 2009·Journal of Chemical Biology·Erick J Dufourc
Jan 1, 1991·The International Journal of Biochemistry·T Cserháti, M Szögyi
Sep 27, 1990·Biochimica Et Biophysica Acta·P Kaszycki, Z Wasylewski
May 7, 1990·Biochimica Et Biophysica Acta·C E Dempsey
Nov 9, 1992·Biochimica Et Biophysica Acta·J R Rydall, P M Macdonald
Aug 26, 2009·Biochimica Et Biophysica Acta·Marise OuelletMichèle Auger
Sep 30, 2008·Biophysical Journal·Frantz Jean-FrançoisErick J Dufourc
Jan 1, 1991·Progress in Biophysics and Molecular Biology·M S Sansom

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