(70c) Self-Assembly of Proteins: The Role of Shape and Specific Interaction

Crystallization is routinely exploited for understanding protein structure, but
the molecular details of how proteins crystallize remain poorly understood. Using computer
simulations, we investigate the role of patchy interactions and protein shape
in self-assembly. We demonstrate that for green fluorescent
protein with its beta-barrel shape, a patchy sphere model is not sufficient to
explain the experimentally observed unit cell, but a model that accounts for
anisotropic shape can reproduce protein crystal growth. We explore
the role of rigid molecular shape in simulations of hard proteins represented
solely by their solvent excluded surfaces. Hard convex polyhedra are known to
crystallize into a multitude of close-packed structures, but for concave shapes
such as proteins much less is known. In our simulations we observe
metastable order, which could shed light on the role of shape in protein
crystal nucleation.