Controlling the length of protein filaments is a major goal in the protein engineering side of synthetic biology. Protein filaments are proteins which interact through two interfaces, producing long two-dimensional filaments. They can be converted to nanoscale devices by fusing functional elements to them such as enzymes or electronically conductive groups.
During my PhD, I approached the goal of controlling filament length with 'capping proteins', which are mutated variants of natural filamentous proteins with one disrupted interface. I set out to create a nanoscale 'mould' out of DNA that could be used to guide filament assembly.