Fractal globule as an artificial molecular machine and hierarchical polymer crumpling
Prof. Sergei Nechaev (LPTMS, Orsay, France)

The relaxation of an elastic network, constructed by a contact map of a fractal (crumpled) polymer globule is investigated. It is found that: i) the slowest mode of the hierarchically folded globule is separated from the rest of the spectrum by a wide gap, and ii) the elastic network quickly relaxes to a low-dimensional (one-dimensional, in our demonstration) manifold spanned by slowest degrees of freedom with a large basin of attraction, and then slowly approaches the equilibrium not escaping this manifold. By these dynamic properties, the fractal globule is similar to real biological molecular machines, like myosin. We have demonstrated that folding and unfolding of a fractal globule can be described as a cascade of equilibrium phase transitions in a hierarchical system. Unfolding manifests itself in a sequential loss of stability of hierarchical levels with the temperature change.