Encapsulation of fragmented cargo by virus coat proteins

Area of Science:

• Biophysics
• Materials Science
• Nanotechnology

Background:

• Co-assembly of nanoparticles and virus coat proteins is crucial for nanotechnology applications.
• Experimental studies show sensitivity to nanocolloid size and nanoparticle-to-protein ratio.
• Larger nanoparticles are preferentially encapsulated in competitive scenarios.

Purpose of the Study:

• To rationalize experimental findings on nanoparticle-virus coat protein co-assembly.
• To investigate the influence of nanoparticle size and stoichiometry on capsid formation.
• To understand the factors governing nanoparticle encapsulation within viral capsids.

Main Methods:

• Development of a simple mass-action model.
• Inclusion of free nanoparticles, coat proteins, and various complex formations.
• Analysis of equilibrium between different molecular species.

Main Results:

• A narrow range of nanocolloid concentrations permits significant partially filled capsid formation.
• The number of encapsulated nanoparticles is typically less than the maximum wall capacity.
• Entropy's impact offsets binding free energy gains, particularly for smaller nanoparticles.

Conclusions:

• The mass-action model qualitatively agrees with experimental observations.
• Entropic effects play a significant role in limiting nanoparticle encapsulation.
• Understanding these principles is key for designing controlled nanoparticle-protein co-assembly systems.