Affinity-based screening of peptides recognizing assembly states of self-assembling peptide nanomaterials.

Novel peptides capable of binding to self-assembled peptide nanomaterials were identified from a random heptapeptide library displayed on phages. Affinity-dependent peptide screening against helically coiled nanofibers constructed of beta-sheet peptides gave phage clones displaying peptides with a variety of affinities and selectivities. An enzyme-linked immunosorbent assay using phage-displayed peptides revealed that the screened peptides specifically bind to target nanofibers, in contrast to reference nanofibers comprised of peptides with slightly different amino acid sequences. A Dot blot assay using chemically synthesized peptides demonstrated that peptide 01 (p01), with the sequence Thr-Gly-Val-Lys-Gly-Pro-Gly, showed an affinity constant (3.7 x 10(5) M(-1)) for the target nanofibers 200 times greater than its affinity for monomeric peptides and 60 times greater than for short nanofibers. These results suggested that p01 selectively recognizes the assembly state of the target peptide. ATR/IR secondary structure analyses clearly showed that when p01 binds to target nanofibers, it undergoes a structural transition from random-coil to parallel beta-sheet structures, resulting in greater affinity and high specificity for the target fiber. Surface modification of the peptide nanofibers by p01 demonstrated that the peptide specifically binds to the edge of the nanofibers. Using p01, uniform arrays of gold nanoparticles (proteins) could be generated on the peptide nanomaterials.