PROBING MOTIONS OF INDIVIDUAL HOLLIDAY JUNCTIONS

Professor Ha uses physical concepts and experimental tools to study fundamental questions in molecular biology. His research program has two main themes: (a) innovative developments of novel tools, including combination of single-molecule fluorescence and mechanical manipulations, and high-throughput single-molecule assays using advanced microfluidics and (b) investigation of molecular mechanisms of helicases, ribozymes, DNA recombination intermediates, chromatic remodeling complexes, and membrane proteins.

DNA recombination is important for repairing such DNA damage as double-strand breaks and for providing raw materials for evolution to choose from. DNA four-way junction, or Holliday junction, is the central intermediate in this process. During his Center appointment, Professor Ha will study the dynamic aspects of the junction lifecycle: how it forms, how it changes shapes, how it migrates, and how it gets resolved into regular duplex DNA. Holliday junctions and their migration have been used to build DNA-based nanomachines, and his approach is likely to generate new insights that will guide emerging fields of nanosciences.