Two-tier supramolecular encapsulation of small molecules in a protein cage

Abstract

Expanding protein design to include other molecular building blocks has the potential to increase structural complexity and practical utility. Nature often employs hybrid systems, such as clathrin-coated vesicles, lipid droplets, and lipoproteins, which combine biopolymers and lipids to transport a broader range of cargo molecules. To recapitulate the structure and function of such composite compartments, we devised a supramolecular strategy that enables porous protein cages to encapsulate poorly water-soluble small molecule cargo through templated formation of a hydrophobic surfactant-based core. These lipoprotein-like complexes protect their cargo from sequestration by serum proteins and enhance the cellular uptake of fluorescent probes and cytotoxic drugs. This design concept could be applied to other protein cages, surfactant mixtures, and cargo molecules to generate unique hybrid architectures and functional capabilities.

A Deferasirox Derivative That Acts as a Multifaceted Platform for the Detection and Quantification of Fe3+

“…The encapsulation of small molecules in HSA and other proteins has gained increasing attention in recent years since it allows the unique electronic environments inside the protein to be accessed while typically providing increased water solubility [46][47][48]. In our case, it was expected to lead to a fluorescent probe.…”

Triggered reversible disassembly of an engineered protein nanocage

“…From bionanoreactors to nanotherapeutic technologies, protein nanocage design presents significant opportunities across numerous research fields. While de novo protein cage design has led to several novel biomolecular tools, 34 increasing numbers of natural protein nanocompartments are being discovered that have been refined by evolution for biological activity and biocompatibility whilst also being amenable to rational engineering approaches. 18,35 The recent surge in encapsulin nanocompartment discovery and engineering further emphasizes this point.…”

Ferritin as a Platform for Creating Antiviral Mosaic Nanocages: Prospects for Treating COVID‐19

“…These methods are: the click chemistry approach used to synthesize synthetic polymers inside a heat-shock protein with the objective of encapsulating drugs, [67] the biorthogonal strategy used to encapsulate a cargo in cowpea chlorotic mottle virus (CCMV) nanocage, [68] reversible covalent modification using disulfide bonds, [12,69] and the recently described micellemediated packaging system. [70] To deliver a therapeutic peptide, other methods described for encapsulation of a protein in viral capsids are available. [71,72] After encapsulation of a therapeutic, the methods described in Figure 3 could be used to cover the surface of the nanocages with neutralizing antibodies or their Fabs, or with nanobodies.…”

“…To improve the encapsulation capacity of nanocages for a therapeutic drug, three alternative methods previously described using other protein nanocages could be applied. These methods are: the click chemistry approach used to synthesize synthetic polymers inside a heat‐shock protein with the objective of encapsulating drugs, [67] the biorthogonal strategy used to encapsulate a cargo in cowpea chlorotic mottle virus (CCMV) nanocage, [68] reversible covalent modification using disulfide bonds, [12,69] and the recently described micelle‐mediated packaging system [70] . To deliver a therapeutic peptide, other methods described for encapsulation of a protein in viral capsids are available [71,72] .…”