Researchers at Kanazawa University report in the
Journal of Physical Chemistry Letters how high-speed atomic force microscopy can be used for studying DNA wrapping processes. The technique enables visualizing the dynamics of DNA–protein interactions, which in certain cases resembles the motion of inchworms.
The genetic material of most organisms is carried by DNA, a complex organic molecule. DNA is very long — for humans, the molecule is estimated to be about 2 m in length. In cells, DNA occurs in a densely packed form, with strands of the molecule coiled up in a complicated but efficient space-filling way. A key role in DNA's compactification is played by histones, structural-support proteins around which a part of a DNA molecule can wrap. The DNA–histone wrapping process is reversible — the two molecules can unwrap and rewrap — but little is known about the mechanisms at play. Now, by applying high-speed atomic-force microscopy (HS-AFM), Richard Wong and colleagues from Kanazawa University (NanoLSI WPI) provide valuable insights into the spatiotemporal dynamics of DNA–histone interactions.