Effect of Mechanical Properties on Multicomponent Shell Patterning.

Self-organized shells are fundamental in biological compartmentalization. They protect genomic material or enclose enzymes to aid the metabolic process. Studies of crystalline shells have shown the importance of the mechanical properties of building units in the shell morphology. However, the mechanism underlying the morphology of multicomponent assemblies is still poorly understood. Here, we analyze multicomponent closed shells that have different mechanical properties. By minimizing elastic energy, we show that heterogeneous bending rigidities regulate the surface pattern into circular, spikes, and ridge shapes. Interestingly, our continuum elasticity model recovers the patterns that have been proposed in bacterial microcompartments (BMCs), which are self-organized protein shells that aid the breakdown of complex molecules and allow bacteria to survive in hostile environments. In addition, our work elucidates the principles of pattern formation that can be used to design and engineer multicomponent microcompartments with a specific surface distribution of the components.