Molecular arrangement of lipid modified amino acids at the solid-liquid interface of highly oriented pyrolytic graphite

Peptides and their derivatives are of special interest in biological as wel l as in chemical systems. They play an essential role in biological transpo rt as the peptides are basic components of protein molecules which form ion channels, receptors, etc. We report on scanning tunnelling microscopy investigations of lipid modifie d amino acid derivatives concerning their organisation on the solid-liquid interface of highly oriented pyrolytic graphite. The molecular order is obs erved experimentally and is correlated to simulation data. In addition, we present the effect of introducing a second alkyl chain on the opposite side of the peptide unit, which is expected to change the molecular organisatio n. Furthermore, we investigated the behaviour of mixed layers consisting of fatty acid molecules and lipid modified peptides. These mixtures might ser ve as a simplified model of biological systems. (C) 2001 Elsevier Science B .V. All rights reserved.