Conformation of Gramicidin in Monolayers, Organic Solvents and Phospholipid Bilayers.
- Other Title
- Conformation of Gramicidin in Monolayer
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The properties of gramicidin and its action on membranes were investigated by the use of monolayers, organic solvents and phospholipid vesicles in relation to cation-binding. The behavior of a gramicidin monolayer was strongly dependent on the organic solvent in which it was dissolved, showing the dependence of the solvent history. A gramicidin monolayer prepared from an ethanol solution caused a large conformational change upon the binding of K+, whereas that prepared from a 2,2,2-trifluoroethanol (TFE) solution showed no conformational change upon the binding of K+. In two organic solvents, gramicidin showed a different calorimetric behavior, due to a difference in conformation. Gramicidin in ethanol markedly decreased the phase-transition temperature and transition enthalpy (ΔH) upon the binding of K+, whereas gramicidin in TFE did not change in calorimetric behavior upon the binding of K+. Incorporating gramicidin into lipid bilayers led to a broadening of the transition and a decrease in the ΔH of the lipid, showing that about 20 lipid molecules per gramicidin molecule were immobilized. By binding K+ to the gramicidin channel, the perturbing effect of gramicidin for the lipid bilayers was depressed, implying aggregation among the peptide channels.
- Bulletin of the Chemical Society of Japan
Bulletin of the Chemical Society of Japan 70 (4), 841-846, 1997
The Chemical Society of Japan