Programming Multidomain Peptides With Molecular Frustration Into Biomolecular Condensates

The discovery of biomolecular condensates, driven by liquid-liquid phase separation of intrinsically disordered proteins has significant impacts on both fundamental and applied science and engineering. Although most studies on biomolecular condensates focus on intrinsically disordered structures, research on the role of molecular ordering remains largely unexplored, however is beneficial for gaining new mechanistic understanding and further expand the design space of peptides for constructing functional condensates. Toward this goal, we conducted systematic studies on how molecular ordering impacts the phase behaviors of peptides using multidomain peptides (MDPs) as a model system. MDPs were designed using a molecular frustration principle in which parts of the peptides favored β-sheet assembly and parts favored disassembly. Through programming of each domain, it is evident that the phase behavior of MDPs is largely dictated by the secondary structure, and partially folded β-sheet plays a key role in driving MDPs to form condensates. We also discovered complex coacervates formed by MDPs and synthetic anionic polymers, which exhibited dramatically improved stability. Furthermore, we show enzyme-triggered condensation can be achieved using phosphorylated MDPs as the molecular precursor and alkaline phosphatase as a molecular switch, highlighting the potential of these materials for bacterial imaging and antimicrobial therapy development.