Close-Packed Sphere structure Coating

Multiple interactions in the same plane can lead to the formation of sheets where, for example, each monomer can interact with six neighbors in a hexagonal close-packing arrangement (Fig. 5-8). Sheets can, with a slight readjustment, be converted into cylindrical tubes (Fig. 5-8) or even into spheres. These closed structures can provide even greater stability since they maximize the number of interactions that can be made. The protein coats of certain viruses are excellent examples of this. Microtubules, which consist of the protein tubulin, can be converted readily between sheet and tubular forms, at least in the purified form. 

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