Local coil–helix transition of semiflexible polymers confined in spheres

Abstract

An off-lattice Monte Carlo method is used to study the conformations of semiflexible polymer chains confined in spheres. The local coil–helix transition is observed for the chains with moderate rigidity confined in small spheres, and the helical structures can be identified by the combination of the dihedral angles and the correlation functions between the tangent vectors. Through calculating the average number of monomers per helix turn, the average number of helix turns per chain, and the ratio of average helix pitch to average helix radius, we find that the radius of the confining sphere and the bending energy are the key factors in the formation of helical structures. This study can help us understand how DNA chains fold in confined spaces, such as viruses and cells.