%0 Journal Article
%@ 0031-9007
%A Morrison, Greg
%A Hyeon, Changbong
%A Hinczewski, Michael
%A Thirumalai, D.
%D 2011
%F eprints:1825
%I American Physical Society
%J Physical Review Letters
%K PACS: 87.10.-e, 87.15.Cc, 87.64.Dz, 87.80.Nj  
%P 138102
%T Compaction and tensile forces determine the accuracy of folding landscape parameters from single molecule pulling experiments
%U http://eprints.imtlucca.it/1825/
%V 106
%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.
%Z © 2011 American Physical Society