Programmable Multiphasic Condensates Formed via Evaporation–Induced Phase Separation of Minimal Peptide Model

Programmable short peptide condensates with intrinsic enzyme-like activity.

The formation of active and catalytic biomolecular condensates is critical to orchestrate intracellular biochemical reactions and cellular functions. Synthetic analogues that mimic such behaviors are typically constructed via liquid-liquid phase separation that generates liquid coacervate-based droplets, which promote reaction efficiency through molecular confinement. Such a type of confined reaction is usually achieved by partitioning and sequestrating active species such as biological enzymes or their mimics (such as metalloenzymes), which can be easily affected by encapsulation efficiency and sensitivity to the local environment. Engineering coacervate-based compartments that can display inherent catalytic functionality remains a significant challenge. Here, we report a bioinspired strategy to construct programmable peptide-based coacervates with inherent enzyme-like catalytic activity via the co-assembly of short peptides. We find that mixing the histidine-tagged short peptides with triphenylalanine-based peptides leads to the formation of a stable coacervate phase, in contrast to the rigid aggregates formed by each individual component. This cooperative assembly enables the generation of functional coacervate compartments with built-in catalytic capability. The resulting peptide coacervates exhibit selective partitioning and sequestration of hydrophobic substrates, thereby enhancing local substrate concentration and promoting catalytic hydrolysis reactions. Our results demonstrate that catalytic activity can be encoded directly into coacervate-forming building blocks through rational peptide design, providing a versatile platform for programming LLPS behavior and constructing biomimetic active materials with potential applications in synthetic biology.

Synthetic Biomolecular Condensates: Design Principles and Applications.

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.

Temperature-Triggered Nanoscale Morphological Transitions in a Synthetic Intrinsically Disordered Protein

Peptide self-assembly and liquid–liquid phase separation (LLPS), often mediated by intrinsically disordered regions (IDRs), are natural mechanisms that translate protein molecular features into complex nano- and mesoscale architectures. Although the thermodynamics and kinetics of these processes are well understood, synthetic materials integrating both functionalities remain rare. Inspired by the conserved IDR–assembly domain (AD) architecture of amyloidogenic proteins, we hypothesized that modular recombinant constructs combining LLPS-capable IDRs with β-sheet-forming ADs could generate materials with tunable structural properties. To test this, we engineered a library of elastin-like polypeptides (ELPs) fused to amphiphilic anionic or cationic amyloidogenic peptides, enabling systematic investigation of how sequence parameters─including ELP length, AD charge, and hydrophilicity─and environmental conditions, including temperature, pH, and salt concentration, influence material behavior. Our results reveal links between molecular design and emergent multiscale structures, including micelles and vesicles embedded within coacervates. This work provides a framework for designing hybrid proteins coupling LLPS and self-assembly.

Engineering Heterotypic Biomolecular Condensates with Synthetic Peptides for Controlled Spatial Organization and Liquid-like Nature

Topology-Encoded Charge Polarity Governs Multiphase Organization in Intrinsically Disordered Protein Polymer Condensates.

Synthetic biomolecular condensates offer a route to engineer compartmentalized microenvironments with tunable physicochemical properties, yet design principles for controlling their internal organization remain limited. Here, we report a minimal two-component system based on thermoresponsive intrinsically disordered protein polymers with lower critical solution temperature behavior (LCST-IDPPs), in which electrostatic topology programs liquid-liquid phase separation (LLPS). Incorporating charged residues into LCST-IDPPs suppresses phase separation under physiological conditions, whereas mixing oppositely charged, individually non-coacervating IDPPs restores LLPS as an emergent, composition-dependent process driven by multivalent intermolecular charge compensation. We compare this two-component system with a covalently linked diblock containing the same charged chains. This change in chain connectivity alters the coupling between electrostatic pairing, counterion redistribution, and LCST-driven dehydration. As a result, the balance between inter- and intrachain ionic pairing encodes the residual charge and micropolarity of the dense phase. This topology-dependent microenvironment controls condensate miscibility and drives the formation of either homogeneous or internally demixed multiphase assemblies. The condensate interior also shifts the apparent pKa of ionizable residues, indicating that phase separation modifies local acid-base equilibria and alters the effective side-chain charge. Together, these findings show how electrostatic topology influences LLPS, the dense-phase microenvironment, and mesoscale organization in IDPP condensates.