AN INFRARED STUDY OF THE INCORPORATION OF ION CHANNEL FORMING PEPTIDES INTO LANGMUIR-BLODGETT-FILMS OF PHOSPHATIDIC-ACID

The incorporation of the channel-forming peptide mixture gramicidin D into multilayer phosphatidic acid films has been achieved by the codeposition of a 16:1 lipid/peptide layer over a subphase of ultrapure water using the Langmuir-Blodgett technique. Over 100 layers of the mixture have been produced with a deposition ratio of 1.0 +/- 0.1 maintained throughout the experiment. The films have been examined by ellipsometry and FTIR spectroscopy and are shown to be highly ordered with the alkyl chains of the lipids at an angle of 78 +/- 3-degrees to the substrate plane. Dichroism in the infrared spectra of the mixture indicates that the peptide is in a channel-forming conformation.