Random RNA under tension

François David1, Christian Hagendorf1,2, Kay Jörg Wiese2
1SPhT-Service de Physique Théorique, CEA/Saclay - 91191 Gif-sur-Yvette Cedex, France
2CNRS-Laboratoire de Physique Théorique de l'Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, France

Abstract

The Lässig-Wiese (LW) field theory for the freezing transition of random RNA secondary structures is generalized to the situation of an external force. We find a second-order phase transition at a critical applied force f = fc. For f < fc forces are irrelevant. For f > fc, the extension L as a function of pulling force f scales as L(f) ~ (f-fc)1/γ-1. The exponent γ is calculated in an epsilon-expansion: At 1-loop order γ = 1/2, equivalent to the disorder-free case. At 2-loop order γ = 0.6. Using a locking argument, we speculate that this result extends to the strong-disorder phase.


q-bio.BM/0701049[pdf]
EPL 78 (2007) 68003 [pdf]


Copyright (C) by Kay Wiese. Last edited March 17, 2008.