Induction of protein-like molecular architecture by self-assembly processes

One of the most intriguing self-assembly processes is the folding of peptide chains into native protein structures. We have developed a method for building protein-like structural motifs that incorporate sequences of biological interest. A lipophilic moiety is attached onto an N(alpha)-amino group of a peptide chain, resulting in a 'peptide-amphiphile'. The alignment of amphiphilic compounds at the lipid solvent interface is used to facilitate peptide alignment and structure initiation and propagation. Peptide-amphiphiles containing potentially triple-helical structural motifs have been synthesized. The resultant head group structures have been characterized by circular dichroism and NMR spectroscopies. Evidence for a self-assembly process of peptide-amphiphiles has been obtained from: (a) circular dichroism spectra and melting curves characteristic of triple-helices, (b) one- and two-dimensional NMR spectra indicative of stable triple-helical structure at low temperatures and melted triple-helices at high temperatures, and (c) pulsed-field gradient NMR experiments demonstrating different self-diffusion coefficients between proposed triple-helical and non-triple-helical species. The peptide-amphiphiles described here provide a simple approach for building stable protein structural motifs using peptide head groups.

Construction of biologically active protein molecular architecture using self-assembling peptide-amphiphiles

The peptide-amphiphiles described here provide a simple approach for building stable protein structural motifs using peptide head groups. One of the most intriguing features of this system is the possible formation of stable lipid films on solid substrates, or the use of the novel amphiphiles in bilayer membrane systems, where the lipid tail serves not only as a peptide structure-inducing agent but also as an anchor of the functional head group in the lipid assembly. The peptide-amphiphile system potentially offers great versatility with regard to head and tail group composition and overall geometries and macromolecular structures. For building materials with molecular and cellular recognition capacity, it is essential to have a wide repertoire of tools to produce characteristic supersecondary structures at surfaces and interfaces.