A structural study of the self-assembly of a palmitoyl peptide amphiphile

Peptide amphiphiles consisting of a hydrophobic alkyl tail coupled to the eight-amino acid GANPNAAG have been studied extensively for their fibre forming properties. However, detailed characteristics of the fibre structure, such as peptide conformation and molecular organisation, are unknown to date. In this report a range of characterization techniques is described that have been employed to elucidate the internal structure of these fibres. Based on the results obtained by circular dichroism spectroscopy, X-ray diffraction and solid state NMR spectroscopy it was concluded that in a self-assembled state the peptide is in a stretched beta-sheet conformation, with the alkyl tails interdigitated and hydrogen-bonded along the axis of the fibre.