Using Circadian Clock Proteins to Self-Assemble Reconfigurable Materials*

Circadian oscillators regulate a variety of metabolic processes. In cyanobacteria, a group of proteins known as KaiA, KaiB, and KaiC regulate the timing of photosynthesis through the rhythmic binding of KaiA and KaiB to KaiC. Previously, we have shown that this system can be repurposed via tagging KaiB with biotin to form bonds with streptavidin coated colloids, allowing for time dependent crosslinking of colloids via KaiB-KaiC complexes. Here we show that this Kai-crosslinking platform can be adapted to a variety of conditions, and map the phase space of dynamic restructuring. We use fluorescence microscopy and image analysis to determine the impact of protein concentrations and colloid size on the material self-assembly and oscillatory crosslinking. We also demonstrate KaiB-KaiC complexes can be used to crosslink biopolymers and hydrogels, each resulting in unique self-assembly kinetics and resulting structure. The adaptability of this novel system makes it useful for a multitude of applications ranging from wound-healing to responsive filtration.