We investigated long, de novo designed coiled-coils based on natural tropomyosin. Due to their modularity and specific binding, they offer great potential in the development of nanomaterials and biomedical applications. From the world of DNA nanotechnology, we wanted to transfer the principle of toehold mediated strand displacement to coiled-coils. We focused on the tropomyosin pair C12, D12 and their variants, which we successfully expressed, isolated and purified. Using a combination of size-exclusion chromatography with multi-angle light scattering (SEC-MALS), circular dichroism (CD) and isothermal titration calorimetry (ITC), we confirmed their molecular weight, secondary structure and binding affinity. Using the NanoLuc split luciferase method, we determined the dissociation constant. Using fluorescence resonance energy transfer (FRET) and split luciferase NanoLuc methods, we also demonstrated the possibility of partial toehold mediated strand displacement of coiled-coils, confirming that coiled-coils have the potential for the design of dynamic protein systems.
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