Coiled-Coil Domains for Self-Assembly and Sensitivity Enhancement of Protein–Polymer Conjugate Biosensors

While protein self-assembly has been used to improve the performance of biosensors and biocatalysts, few general techniques have been demonstrated to achieve well-ordered protein arrays under the highly concentrated conditions required to optimize device performance. The strong association strength of coiled-coils, supercoiled bundles of alpha helices wrapped around each other, makes these structures promising scaffolds from which proteins can be linked into ordered assemblies in concentrated solution. Herein, the two component alpha helices of a heterodimeric coiled-coil are fused to a weakly ordering protein, 2x rcSso7d.SA (2x), to improve its self-assembly as a protein–poly(N-isopropylacrylamide) (PNIPAM) conjugate. Three fusion protein conjugates are developed, from which two distinct heterodimeric coiled-coil conjugates are formed, but only one of these heterodimer conjugates significantly improves the ordering quality of 2x. Additionally, the alpha helical segment in one of the three synthesized fus...