Peptides
amphiphile couple the specific functionality of proteins with the engineering
convenience of synthetic amphiphiles. Theses molecules covalently link a
peptide head-group, typically from active fragment of a larger protein, to
hydrophobic alkyl tail. Our research is aimed at forming and characterizing
covalently stabilized self-assembled peptide-amphiphiles aggregates, that can
be used as a platform for examination and design of biological systems. We have
studied the self-assembly properties of a model DNA binding amphiphile, having
a GCN4 peptide as the head group and polymerizble (methacrylic) group in the
tail region, using a combination of small-angle x-ray scattering and cryo-
transmission electron microscopy. Our results revealed a variety of
self-assembled structures. Moreover, opposing common surfactants, the specific
interaction between the head-groups seems to play an important role in
determining the microstructure. In aqueous solution, these peptide amphiphiles
assembled into helical ribbons and tubules (hollow cylinders). The geometry of
the self-assembled aggregate could be controlled by means of adding a
co-surfactant. For example, addition of SDS induced formation spherical
micelles, whereas adding Triton x-100 has lead to transition into thread-like
micelles.
