Dynamic Surface Layer Coiled Coil Proteins Processing Analog-to-Digital Information

Surface layer proteins perform multiple functions in prokaryotic cells, including cellular defense, cell-shape maintenance, and regulation of import and export of materials. However, mimicking the complex and dynamic behavior of such two-dimensional biochemical systems is challenging, and hence research has so far focused mainly on the design and manipulation of the structure and functionality of protein assemblies in solution. Motivated by the new opportunities that dynamic surface layer proteins may offer for modern technology, we herein demonstrate that immobilization of coiled coil proteins onto an inorganic surface facilitates complex behavior, manifested by reversible chemical reactions that can be rapidly monitored as digital surface readouts. Using multiple chemical triggers as inputs and several surface characteristics as outputs, we can realize reversible switching and logic gate operations that are read in parallel. Moreover, using the same coiled coil protein monolayers for derivatization of nanopores drilled into silicon nitride membranes facilitates control over ion and mass transport through the pores, thereby expanding the applicability of the dynamic coiled coil system for contemporary stochastic biosensing applications.