Markov Chain Monte Carlo Methods for Simulations of Biomolecules

Berg, Bernd A.

doi:10.1007/978-3-540-74029-2_12

Cited by 2 publications

References 81 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Free-energy calculations for semi-flexible macromolecules: Applications to DNA knotting and looping

Giovan

Scharein²,

Hanke

et al. 2014

The Journal of Chemical Physics

View full text Add to dashboard Cite

We present a method to obtain numerically accurate values of configurational free energies of semiflexible macromolecular systems, based on the technique of thermodynamic integration combined with normal-mode analysis of a reference system subject to harmonic constraints. Compared with previous free-energy calculations that depend on a reference state, our approach introduces two innovations, namely, the use of internal coordinates to constrain the reference states and the ability to freely select these reference states. As a consequence, it is possible to explore systems that undergo substantially larger fluctuations than those considered in previous calculations, including semiflexible biopolymers having arbitrary ratios of contour length L to persistence length P. To validate the method, high accuracy is demonstrated for free energies of prime DNA knots with L/P = 20 and L/P = 40, corresponding to DNA lengths of 3000 and 6000 base pairs, respectively. We then apply the method to study the free-energy landscape for a model of a synaptic nucleoprotein complex containing a pair of looped domains, revealing a bifurcation in the location of optimal synapse (crossover) sites. This transition is relevant to target-site selection by DNA-binding proteins that occupy multiple DNA sites separated by large linear distances along the genome, a problem that arises naturally in gene regulation, DNA recombination, and the action of type-II topoisomerases.

show abstract