Coupled conformational equilibria in β-sheet peptide-dendron conjugates

A series of peptide-dendron conjugates, based on an intrinsically alpha-helical, alanine-rich sequence, were constructed to explore how the conformational equilibria of each structural element can be conformationally coupled. The interdendron spacing was varied from i, i + 4 (2) to i, i +11 (9) to probe how the nature of the dendron interaction impacted the conformational properties. These studies revealed an alpha-helix to beta-sheet conformational transition that occurred in water for peptide-dendron conjugates 4 (i, i + 6) and 8 (i, i + 10). Chiral transfer from the peptide backbone to the dendron helicity emerges only in the beta-sheet forms of 4 and 8, revealing a synergistic coupling of the conformations of both structural elements.