Branchpoint Structure of DNA Threeway Junctions

Branched structures of nucleic acids are widely observed in nature as intermediates during DNA repair, recombination and replication processes, as well as being a component of vital structures for protein synthesis. Using highresolution single-molecule Fo╮ster resonance energy transfer (SM-FRET), we showed recently that a DNA three way junction was not fully paired at the branchpoint, in spite of being fully complementary.(1) To investigate whether this expanded branchpoint was a general effect, or due to the specific sequence used, we have also studied a three-way junction with a GC-rich branchpoint. We report the results of SM-FRET and ensemble NMR experiments on this new junction, together with initial investigations of the branchpoint reactivity. 1. Sabir, Tara et al. "Branchpoint Expansion in a Fully Complementary ThreeWay DNA Junction." J. Am. Chem. Soc. (2012) 134: 6280 6285

http://dx.doi.org/10.1016/j.bpj.2015.11.1025