Templated Assembly of a Functional Ordered Protein Macromolecular Framework from P22 Virus-like Particles

Abstract

Bottom-up construction of mesoscale materials using biologically derived nanoscale building blocks enables engineering of desired physical properties using green production methods. Virus-like particles (VLPs) are exceptional building blocks due to their monodispersed sizes, geometric shapes, production ease, proteinaceous composition, and our ability to independently functionalize the interior and exterior interfaces. Here a VLP, derived from bacteriophage P22, is used as a building block for the fabrication of a protein macromolecular framework (PMF), a tightly linked 3D network of functional protein cages that exhibit long-range order and catalytic activity. Assembly of PMFs was electrostatically templated, using amine-terminated dendrimers, then locked into place with a ditopic cementing protein that binds to P22. Long-range order is preserved on removal of the dendrimer, leaving a framework material composed completely of protein. Encapsulation of β-glucosidase enzymes inside of P22 VLPs results in formation of stable, condensed-phase materials with high local concentration of enzymes generating catalytically active PMFs.

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]…”

The phage L capsid decoration protein has a novel OB-fold and an unusual capsid binding strategy

“…Previous work has shown that P22 and phage L behave similarly [33,34,36] and all of the amino acid substitutions found in phage L have even been identified occasionally in P22 stocks as phenotypically silent mutations (Teschke lab, unpublished data). Lastly, as Dec bound to P22 is a widely used system for a variety of nanomaterials applications [10,42,43], identifying key residues that contribute to Dec interactions with P22 is highly useful for practical applications. Therefore, we felt it reasonable to use the established genetics of P22 as a model for the native phage L for our mutagenesis studies.…”

Virus‐Like Particles as Theranostic Platforms

“…[ 50–52 ] Moreover, the assembly of VLPs can be promoted, templated, and even controlled by heterologous biomolecules, organic molecules (e.g., polymers), or inorganic NPs with the appropriate features (e.g., a negative charge to promote the assembly of VLPs with a positively charged inner surface). [ 53–56 ] Three basic general strategies for capsid assembly are recognized ( Figure ): i) capsid self‐assembly, ii) scaffolding‐protein‐assisted capsid assembly, and iii) viral‐nucleic‐acid‐assisted capsid assembly.…”

“…Virus‐like NPs are also used in applications such as RNA and enzyme delivery and protein supplementation. [ 55,80,118,149 ] MS2 VLPs displaying the TAT peptide on their surfaces effectively penetrated the cytomembrane and delivered microRNA‐122. The inhibitory effects of microRNA‐122 on hepatocellular carcinoma were significant in Hep3B, HepG2, and Huh7 cells and in Hep3B‐related animal models.…”