Characterizing and controlling nanoscale self-assembly of suckerin-12

Structural proteins such as the “suckerins” present promising avenues for fabricating functional materials. Suckerins are a family of naturally occurring block copolymer-type proteins that comprise the sucker ring teeth of cephalopods and are known to self-assemble into supramolecular networks of nanoconfined β -sheets. Here, we report characterization and controllable, nanoscale self-assembly of suckerin-12 (S12). We characterize impacts of salt, pH, and protein concentration on S12 solubility, secondary structure, and self-assembly. In doing so, we identify conditions for fabricating ~100 nm nanoassemblies (NAs) with narrow size distributions. Finally, by installing a non-canonical amino acid (ncAA) into S12, we demonstrate the assembly of NAs that are covalently conjugated with a hydrophobic fluorophore, and the ability to change self-assembly and β -sheet content by PEGylation. This work presents new insights into the biochemistry of suckerin-12 and demonstrates how ncAAs can be used to expedite and fine-tune the design of protein materials.