Autonomous Self-Pulsation of Protein Vesicles via Substrate-Induced Protein Allosteric Cycle

Oscillatory phenomena in organisms are vital to sustaining life rhythms, like the pulsation of cardiac muscle cells. Mimicking such biotic oscillating behaviors to realize periodic chemical-to-mechanical energy conversion is an essential premise for the assembly of lifelike systems in vitro. Here we report a protein-based vesicle system that can do rhythmic, autonomous pulsation in a nonequilibrium state through a substrate-induced protein allosteric cycle. Organizing protein kinase-polypeptide mega-amphiphiles into a vesicular structure, they show cyclical shrinking and swelling motion due to reciprocating conformational compaction and relaxation of kinase activated by its specific allosteric substrates, ATP and AMP. Moreover, control of the substrate level allows one to regulate the periodicity, amplitude, and lifetime of the proteinosome oscillation. This can further periodically change the membrane permeability, thus offering the ability to program the transmembrane traffic in synthetic protein-based assemblies.