High-resolution atomic-force microscopy of DNA: the pitch of the double helix.
Using a cationic lipid bilayer, we show that DNA can be reliably adsorbed to the bilayer surface for atomic force microscopy (AFM) in aqueous buffers at high resolution. The measured width of the dsDNA is close to 2 nm, and a periodic modulation on dsDNA is reproducibly detected by the AFM. The measured period is 3.4 +/- 0.4 nm, in excellent agreement with the known pitch of the double helix. The right-handedness of the double helix is directly discernible in high resolution AFM images. Thus, this approach can be readily applied to the study of DNA-protein interactions, as well as sequence mapping at high resolution.
Mou
J
J
Department of Molecular Physiology and Biological Physics, University of Virginia Health Sciences Center, Charlottesville 22908, USA.
Czajkowsky
D M
DM
Zhang
Y
Y
Shao
Z
Z
D004247:DNA / Q000737:chemistry*; D004269:DNA, Bacterial / Q000737:chemistry; D008567:Membranes, Artificial; D018625:Microscopy, Atomic Force; D009690:Nucleic Acid Conformation; D015203:Reproducibility of Results
D004269:DNA, Bacterial; D008567:Membranes, Artificial; D004247:DNA