Conformational Switching of Proteins on Material Surfaces Enabled by Peptide‐Oriented Adsorption

ABSTRACT Conformationally responsive proteins are increasingly being harnessed to build stimulus‐responsive biointerfaces, yet the interconversion dynamics of proteins are routinely lost upon adsorption to inorganic surfaces. Heterogeneous protein attachment, driven by the stochastic presentation of surface‐interactive residues, can occlude active sites, mask allosteric interfaces, and diminish the dynamic properties the protein was recruited to provide. Here, we demonstrate a genetically encoded strategy to preserve conformational switching by biasing surface attachment through the modification of calmodulin (CaM) with a Au binding domain, the AuBP1 peptide, to promote a preferred adsorption geometry at aqueous Au interfaces. Quartz crystal microbalance with dissipation measurements reveal fully reversible viscoelastic changes in the adsorbed layer for CaM fused to AuBP1 across multiple Ca 2+ binding/release cycles with no measurable mass loss, which was absent for wild‐type CaM. Atomic force microscopy independently confirmed conformation‐dependent surface morphologies for the apo and holo states. Molecular dynamics simulations support a dominant AuBP1‐mediated binding configuration that minimizes disruptive surface contacts. These observations identify transferable design principles for switchable biointerfaces and establish that non‐covalent peptide‐mediated orientation can sustain functional protein dynamics in direct contact with a metal without reliance on covalent immobilization.