%P 138102
%T Compaction and tensile forces determine the accuracy of folding landscape parameters from single molecule pulling experiments
%I American Physical Society
%V 106
%O ? 2011 American Physical Society
%X We establish a framework for assessing whether the transition state location of a biopolymer, which can be inferred from single molecule pulling experiments, corresponds to the ensemble of structures that have equal probability of reaching either the folded or unfolded states (Pfold=0.5). Using results for the forced unfolding of a RNA hairpin, an exactly soluble model, and an analytic theory, we show that Pfold is solely determined by s, an experimentally measurable molecular tensegrity parameter, which is a ratio of the tensile force and a compaction force that stabilizes the folded state. Applications to folding landscapes of DNA hairpins and a leucine zipper with two barriers provide a structural interpretation of single molecule experimental data. Our theory can be used to assess whether molecular extension is a good reaction coordinate using measured free energy profiles.
%L eprints1825
%D 2011
%A Greg Morrison
%A Changbong Hyeon
%A Michael Hinczewski
%A D. Thirumalai
%K PACS: 87.10.-e, 87.15.Cc, 87.64.Dz, 87.80.Nj

%R 10.1103/PhysRevLett.106.138102
%J Physical Review Letters