Elastin-like protien-globular protein fusion constructs as a method for high-throughput self-assembly of functional nanostructures

The self-assembly of proteins into functional nanostructured materials offers the opportunity for substantial improvement in the performance of materials such as biocatalysts and biosensors. Typically, these materials are developed by adopting a protein that was previously optimized for function in solution and repurposing it in a solid state or interfacial context. However, this may not lead to optimum function of the overall material. Here, we show a method for preparing protein-based materials in high-throughput based on fusion protein self-assembly. First, we demonstrate that elastin-like protein (ELP) fusions, originally developed as solubility-enhancing tags, can also be engineered in order to promote self-assembly of the protein materials into block copolymer-like nanostructures, similarly to synthetic polymer-protein bioconjugates. The design of the ELP block to promote self-assembly, including charge and hydrophobicity, is explored. Then, we show that the use of the ELP as a protein purification tag enables high throughput material fabrication. In particular, the discovery of cononsolvency of the ELPs enables development of a precipitation-based purification process that can yield purified protein samples with very low residual salt, producing robust self-assembled structures. This process can be generalized to a variety of different proteins that are tolerant of the cononsolvent. The ability to use this technology in well plate format to generate material libraries is then demonstrated.