Single molecular observation of DNA and DNA complexes by atomic force microscopy

Atomic force microscopy (AFM) provides a novel way to understand the structure-function relationship of protein synthesis at a single-molecular level. High-resolution AFM imaging in air, liquid and vacuum allows for single DNA, RNA and proteins to be observed at the nano-scale in addition to their conformational transitions, bound states, temporal behavior, and assembly. The recent development of frequency modulation mode AFM has led to imaging hydration structures of DNA in water and molecular polarization of DNA complexes in vacuum. Real-time imaging in near-physiological environments captures transcriptional activation with characteristic conformation of DNA-protein complexes. We review current achievements and the future potential of methodological and biological AFM to reveal insights into DNA, RNA and their complexes.