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Coupled Conformational Equilibria in Peptide-Dendron Conjugates
Jon R. Parquette, Department of Chemistry, The Ohio State University, Columbus, OH 43210
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 peptidedendron 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) peptidedendron 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.
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Dendron
s
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