2. Coupled Conformational Equilibria in Peptide-Dendron Conjugates
Jon R. Parquette, Department of Chemistry, The Ohio State University, Columbus, OH 43210
Dendrons
Sequence A
i, i+11
Ac-AAD*AKAAAAKAAAD*YA-NH2 B
i, i+10
Ac-AAD*AKAAAAKAAD*AYA-NH2 C
i, i+9
Ac-AAD*AKAAAAKAD*AAYA-NH2 D
i, i+8
Ac-AAD*AKAAAAKD*AAAYA-NH2 E
i, i+7
Ac-AAD*AAKAAAD*KAAAYA-NH2 F
i, i+6
Ac-AAD*AKAAAD*AKAAAYA-NH2 G
i, i+5
Ac-AAD*AKAAD*AAKAAAYA-NH2 H
i, i+4
Ac-AAD*AKAD*AAKAAAAYA-NH2 I
Control
Ac-AAAAKAAAAKAAAAYA-NH2
In this work, we are attempting to understand how multiple elements of secondary structure cooperate in determining the conformational properties of synthetic, folded macromolecules. These studies will facilitate the design of materials with novel functions not present in biological materials. Specifically, we have prepared peptide-dendron conjugates based on a polyalanine sequence having a strong tendency to adopt the -helical conformation. Preliminary studies indicate that when the dendrons are incorporated at the i, i+10 (B) or i, i+6 (F) positions the peptides actually adopt a -sheet conformation that further assembles into fibrils. The i, i+10 (B) peptide-dendron hybrid further assembles into a nanotube structure that interconverts with amyloid beta fibrils with changes in pH or NaCl concentration. The assemblies bind and release hydrophobic dyes with pH changes, suggesting applications in drug delivery.