Thickness-dependent secondary structure formation of tubelike polymers

¹  Institut für Theoretische Physik and Centre for Theoretical Sciences (NTZ), Universität Leipzig - Postfach 100 920, D-04009 Leipzig, Germany, EU
²  John von Neumann Institute for Computing (NIC), Forschungszentrum Jülich - D-52425 Jülich, Germany, EU

Corresponding authors: Thomas.Vogel@itp.uni-leipzig.de neuhaus@physik.uni-bielefeld.de Michael.Bachmann@itp.uni-leipzig.de Wolfhard.Janke@itp.uni-leipzig.de

Received: 9 September 2008
Accepted: 27 November 2008

Abstract

By means of sophisticated Monte Carlo methods, we investigate the conformational phase diagram of a simple model for flexible polymers with explicit thickness. The thickness constraint, which is introduced geometrically via the global radius of curvature of a polymer conformation, accounts for the excluded volume of the polymer and induces cooperative effects supporting the formation of secondary structures. In our detailed analysis of the temperature and thickness dependence of the conformational behavior for classes of short tubelike polymers, we find that known secondary-structure segments like helices and turns, but also ringlike conformations and stiff rods are dominant intrinsic topologies governing the phase behavior of such cooperative tubelike objects. This shows that the thickness constraint is indeed a fundamental physical parameter that allows for a classification of generic polymer structures.