Structure of forked DNA in solution revealed by high-resolution single-molecule FRET

Branched DNA structures play critical roles in
DNA replication, repair, and recombination in addition to
being key building blocks for DNA nanotechnology. Here we
combine single-molecule multiparameter fluorescence detection
and molecular dynamics simulations to give a general
approach to global structure determination of branched DNA
in solution. We reveal an open, planar structure of a forked
DNA molecule with three duplex arms and demonstrate an
ion-induced conformational change. This structure will serve
as a benchmark for DNA-protein interaction studies.