Regulating self-assembly of spherical oligomers.

In multistep reactions, stability of intermediates is critical to the rate of product formation and a significant factor in generating kinetic traps. The capsid protein of cowpea chlorotic mottle virus (CCMV) can be induced to assemble into spherical particles of 30, 60, and 90 dimers. Based on examining assembly kinetics and reaction end points, we find that formation of uniform, ordered structures is not always a result of reactions that reach equilibrium. Equilibration or, alternatively, kinetic trapping can be identified by a straightforward analysis. Altering the assembly path of "spherical" particles is a means of controlling the distribution of products, which has broad applicability to self-assembly reactions.