Ideal architecture of residue packing and its observation in protein structures

Abstract
A simple model of sphere packing has been investigated as an ideal model for long‐range interactions for the packing of non‐bonded residues in protein structures. By superposing all residues, the geometry of packing around a central residue is investigated. It is found that all residues conform almost perfectly to this lattice model for sphere packing when a radius of 6.5 Å is used to define non‐bonded (virtual) interacting residues. Side‐chain positions with respect to sequential backbone segments are relatively regular as well. This lattice can readily be used in conformation simulations to reduce the conformational space.