Protein Engineering of a Viral Cage for Constrained Nanomaterials Synthesis

Abstract

Cage architectures based on the cowpea chlorotic mottle virus (see Figure) have been employed to achieve a synthetic mimic of the iron storage protein ferritin. The electrostatic nature of the inner protein surface could be changed by up to 3240 units of charge, while still maintaining a stable cage structure. The spatial isolation within the protein cage prevents bulk aggregation of the mineral particles and results in a stable, mono‐disperse colloid.

Core-controlled polymorphism in virus-like particles

“…The crystals represent a form of metallodielectric material that exhibits optical properties influenced by multipolar plasmonic coupling. metamaterials ͉ protein cage ͉ self-assembly ͉ surface plasmon ͉ virus assembly E ngineered virus capsids and protein cage structures have shown increasing promise as therapeutic and diagnostic vectors (1-6), imaging agents (7-10), and as templates and microreactors for advanced nanomaterials synthesis (11)(12)(13)(14)(15)(16)(17). Here, we address the rules for the formation of symmetric protein cages consisting of viral capsid subunits formed over a functionalized inorganic nanoparticle core, called virus-like particles (VLPs).…”

A virus-based single-enzyme nanoreactor

“…In recent reports, protein capsids and viruses have been studied as containers, as potential reaction vessels [5][6][7][8] , as well-defined hosts [9][10][11][12] , as nanotemplates [13][14][15][16][17][18] and as synthetic platforms [19][20][21] . To the best of our knowledge, no enzyme-loaded nanocontainer has been assembled, let alone studied, at the single-enzyme level.…”

Nanoindentation studies of full and empty viral capsids and the effects of capsid protein mutations on elasticity and strength

“…Thus, by comparing the properties of empty and full capsids it is possible to assess the effect of the protein-RNA interaction on capsid elasticity and strength. CCMV capsids can also assemble spontaneously around a wide variety of anionic polymers (13,14), and this property has raised the possibility of their use as nanocontainers (15).…”

“…Because of the broad interest in CCMV, a number of mutants have been obtained in which substitutions and͞or deletions of residues in the capsid protein have been performed (15)(16)(17)(18), making it possible to explore the effects of the protein primary structure on the mechanical properties. Among them is the salt-stable (ss) mutant, which does not dissociate at pH 7.5 at high ionic strength (i Ͼ 1 M) (16).…”

“…Sequence analysis shows that there is a single substitution of Lys-42 of the capsid protein to arginine. Another mutant, SubE, has the same substitution, but, in addition, the nine basic residues (lysine and arginine) at the N terminus have been replaced by glutamic acid (15). As a result of the charge inversion, RNA cannot be packaged into subE capsids.…”