Topology-dependent swichability of peptide secondary structures in bioconjugates with complex architectures

Abstract

Peptide sequences, which exhibit a reversible pH-responsive coil to α-helix secondary structure transition, are conjugated to polymer precursors to yield linear AB and graft ABA peptide-poly(ethylene oxide) conjugates. While the PEO B-block is comparable, the conjugates differ in topologies of the peptide bearing A-blocks. The influences of topology on the structure transitions in the peptide segments are investigated, comparing linear AB-bioconjugates with graft ABA-bioconjugates having multiple peptide segments combined in star or pom-pom topologies. The effect of conjugate topology on the reversible pH-responsive coil to α-helix secondary structure transition is described. Three peptide-polymer conjugates are synthesized, exhibiting similar poly(ethylenoxid) blocks but differing in topologies of the peptide bearing blocks. The study compares structural transitions and self-assembly of linear AB-bioconjugates with graft ABA-bioconjugates having multiple peptide segments combined in star or pom-pom topologies. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.