Studies on Composition and Sequence Effects in Surface-Mediated Octapeptide Assemblies by Using Scanning Tunneling Microscopy

A set of the homogeneous and heterogeneous octapeptides have been studied for the composition and sequence effects on surface-mediated assemblies at liquid–solid interfaces by using scanning tunneling microscopy. The observed assembly structures on graphite surface reveal that all these peptides can form homogeneous lamella characteristics. By analyzing the distributions of lamella width and intralamella peptide strand length, it is suggested that the composition and sequence of the octapeptides consisting of tryptophan and glycine in the present experiments do not have a significant impact on the observed assembling characteristics. These results indicate that the observed assembling stability on the highly oriented pyrolytic graphite (HOPG) surface is dominated by the main chains of the octapeptides containing tryptophan and glycine, and independent of the bulky moieties of tryptophan in the sequence.