Dual Control of Peptide Conformation with Light and Metal-Coordination.

Abstract

We describe the design of a stimuli-responsive peptide whose conformation is controlled by wavelength-specific light and metal coordination. The peptide adopts a defined tertiary structure whose conformation can be modulated between an α-helical coiled coil and β-sheet. The peptide is designed with a hydrophobic interface to induce coiled coil formation and is based on a recently described strategy to obtain switchable helix dimers. Here, we endowed the helix dimer with 8-hydroxyquinoline (HQ) groups to achieve metal coordination and a shift to a β-sheet structure. We find that the conformational shift only occurs upon introduction of Zn 2+ . The other metal ions (Cu 2+ , Fe 3+ , Co 2+ , Mg 2+ and Ni 2+ ) do not offer switching likely due to non-specific metal-peptide coordination. A control peptide lacking the metal-coordinating residues does not show conformational switching with Zn 2+ supporting the role of this metal in stabilizing the β-sheet conformation in a defined manner.