The self-assembly of proteins into higher-order superstructures is ubiquitous in biological systems. Genetic methods comprising both computational and rational design strategies are emerging as powerful methods for the design of synthetic protein complexes with high accuracy and fidelity. Although useful, most of the reported protein complexes lack a dynamic behavior, which may limit their potential applications. On the contrary, protein engineering by using chemical strategies offers excellent possibilities for the design of protein complexes with stimuli-responsive functions and adaptive behavior. However, designs based on chemical strategies are not accurate and therefore, yield polydisperse samples that are difficult to characterize. Here, we describe simple design principles for the construction of protein complexes through a supramolecular chemical strategy. A micelle-assisted activity-based protein-labeling technology has been developed to synthesize libraries of facially amphiphilic synthetic proteins, which self-assemble to form protein complexes through hydrophobic interaction. The proposed methodology is amenable for the synthesis of protein complex libraries with molecular weights and dimensions comparable to naturally occurring protein cages. The designed protein complexes display a rich structural diversity, oligomeric states, sizes, and surface charges that can be engineered through the macromolecular design. The broad utility of this method is demonstrated by the design of most sophisticated stimuli-responsive systems that can be programmed to assemble/disassemble in a reversible/irreversible fashion by using the pH or light as trigger.

The custom design of protein–dendron amphiphilic macromolecules is at the forefront of macromolecular engineering. Macromolecules with this architecture are very interesting because of their ability to self‐assemble into various biomimetic nanoscopic structures. However, to date, there are no reports on this concept due to technical challenges associated with the chemical synthesis. Towards that end, herein, a new chemical methodology for the modular synthesis of a suite of monodisperse, facially amphiphilic, protein–dendron bioconjugates is reported. Benzyl ether dendrons of different generations (G1–G4) are coupled to monodisperse cetyl ethylene glycol to form macromolecular amphiphilic activity‐based probes (AABPs) with a single protein reactive functionality. Micelle‐assisted protein labeling technology is utilized for site‐specific conjugation of macromolecular AABPs to globular proteins to make monodisperse, facially amphiphilic, protein–dendron bioconjugates. These biohybrid conjugates have the ability to self‐assemble into supramolecular protein nanoassemblies. Self‐assembly is primarily mediated by strong hydrophobic interactions of the benzyl ether dendron domain. The size, surface charge, and oligomeric state of protein nanoassemblies could be systematically tuned by choosing an appropriate dendron or protein of interest. This chemical method discloses a new way to custom‐make monodisperse, facially amphiphilic, protein–dendron bioconjugates.

The rational design of a multi‐responsive protein‐based supramolecular system that can predictably respond to more than one stimulus remains an essential but highly challenging goal in biomolecular engineering. Herein, we report a novel chemical method for the construction of multi‐responsive supramolecular nanoassemblies using custom‐designed facially amphiphilic monodisperse protein‐dendron bioconjugates. The macromolecular synthons contain a globular hydrophilic protein domain site‐specifically conjugated to photo‐responsive hydrophobic benzyl‐ether dendrons of different generations through oligo(ethylene glycol) linkers of defined length. The size of the protein nanoassemblies can be systematically tuned by choosing an appropriate dendron or linker of defined length. Exposure of protein nanoassemblies to light results in partial rather than complete disassembly of the complex. The newly formed protein nanoparticle no longer responds to light but could be disassembled into constitutive monomers under acidic conditions or by further treatment with a small molecule. More interestingly, the distribution ratio of the assembled versus disassembled states of protein nanoassemblies after photochemical reaction does not depend on dendron generation, the nature of the linker functionality or the identity of the protein, but is heavily influenced by the linker length. In sum, this work discloses a new chemical method for the rational design of a monodisperse multi‐responsive protein‐based supramolecular system with exquisite control over the disassembly process.

Protein oligomers are ubiquitous in nature and play an essential role in various biological processes. Recently, there is an enormous interest to custom‐make synthetic protein oligomers through the bottom‐up approach. In this regard, genetic methods have made tremendous progress in the last decade. In comparison, only few chemical methods currently exist for this purpose. Herein, we report a modular synthetic strategy for the design of facially amphiphilic globular protein‐synthetic peptide conjugates. The self‐assembly of these bioconjugates is driven by strong hydrophobic interaction of the peptide domain. The size, molecular mass and oligomeric state of semi‐synthetic protein complexes strongly depend on size and surface charge of a globular protein as well as the length of the hydrophobic peptide domain. A systematic structure‐property relationship study of these semi‐synthetic proteins should shed more light on the understanding of various non‐covalent forces, which governs the oligomerization processes of naturally occurring proteins.

The reversible nature of disulfide functionality has been exploited to design intelligent materials such as nanocapsules, micelles, vesicles, inorganic nanoparticles, peptide and nucleic acid nanodevices. Herein, we report a new chemical methodology for the construction redox-sensitive protein assemblies using monodisperse facially amphiphilic protein-dendron bio-conjugates. The disulfide functionality is strategically placed between the dendron and protein domains. The custom designed bioconjugates self-assembled into nanoscopic objects of a defined size dictated by the nature of dendron domain. The stimuli-responsive behavior of the protein assemblies is demonstrated using a suitable redox trigger.