Overdamped thermal ratchets in one and more dimensions. Kinesin transport and protein folding

摘要

The overdamped thermal ratchet driven by an external (Orstein-Uhlenbeck) noise is revisited. The ratchet we consider is unbounded in space and not necessarily periodic. We briefly discuss the conditions under which current is obtained by analyzing the corresponding Fokker-Planck equation and its lack of stationary states. Next, two examples in more than one dimension and related to biological systems are presented. First, a two-dimensional model of a "kinesin protein" on a "microtubule" is analyzed and, second, we suggest that a ratchet mechanism may be behind the folding of proteins; the latter is elaborated with a multidimensional ratchet model. (c) 2006 Elsevier B.V. All rights reserved.