RNA double strand hybridization measured at the single molecule level

RNA double strand hybridization is a hallmark for gene expression regulation. In this function, single stranded regulatory RNA forms Watson-Crick base pairs with complementary messenger RNA. In the presented work the dissociation constants of complementary equally sized RNA single strands were measured at the single molecule level applying fluorescence correlation spectroscopy (FCS). Dissociation constants of 3.2 nM, 1.4 nM and 1.0 nM were determined for 26 bp, 41 bp and 54 bp dsRNA, respectively. The translational diffusion coefficients of RNA, measured at infinite dilution, could be accurately predicted applying the model D = 4.58 × 10^-10 N^-0.39 m²s^-1.