Modular Self-Assembly of Protein Cage Lattices for Multistep Catalysis

Abstract

The assembly of individual molecules into hierarchical structures is a promising strategy for developing three-dimensional materials with properties arising from interaction between the individual building blocks. Virus capsids are elegant examples of biomolecular nanostructures, which are themselves hierarchically assembled from a limited number of protein subunits. Here we demonstrate the bio-inspired modular construction of materials with two levels of hierarchy; the formation of catalytically active individual virus-like particles (VLPs) through directed self-assembly of capsid subunits with enzyme encapsulation, and the assembly of these VLP building blocks into three-dimensional arrays. The structure of the assembled arrays was successfully altered from an amorphous aggregate to an ordered structure, with a face-centered cubic lattice, by modifying the exterior surface of the VLP without changing its overall morphology, to modulate interparticle interactions. The assembly behavior and resultant lattice structure was a consequence of interparticle interaction between exterior surfaces of individual particles, and thus independent of the enzyme cargos encapsulated within the VLPs. These superlattice materials, composed of two populations of enzyme packaged VLP modules, retained the coupled catalytic activity in a two-step reaction for isobutanol synthesis. This study demonstrates a significant step toward the bottom-up fabrication of functional superlattice materials using a self-assembly process across multiple length scales, and exhibits properties and function that arise from the interaction between individual building blocks.

Enzyme encapsulation by protein cages

“…77 Such a reaction has also been demonstrated in P22 which is itself arranged into a higher order, superlattice structure. 64,[78][79][80]…”

Phthalocyanine–Virus Nanofibers as Heterogeneous Catalysts for Continuous‐Flow Photo‐Oxidation Processes

“…Importantly, strategies to control the interaction between the protein and the cocrystallization agent by means of pH and ionic strength of the aqueous media has enabled fine tuning in the kinetics of the assembly process, leading to high structural control. Recent examples of protein crystal scaffolds with catalytic activity indicate that biohybrids can function as efficient catalysts . While protein cages such as (apo)ferritin or cowpea chlorotic mottle virus have coped the most recent developments in 3D electrostatic assemblies, other protein scaffolds such as tobacco mosaic virus (TMV) have been recently explored, yielding unidimensional morphologies …”

Highly ordered protein cage assemblies: A toolkit for new materials

“…Crosslinking treatment of a single crystal enables structural characterization of the formation of a sub‐nanocluster via a reduction reaction (Reprinted with permission from Lach et al (). Copyright 2017 Wiley Online Library, Uchida et al (). Copyright 2018 American Chemical Society, and Maity et al ().…”