(A) Low-magnification AFM topography image of a plasmid showing corrugation. (B) Higher-magnification trace (white arrow to right) and retrace (white arrow to left) images of this area showing corrugation consistent with the B form of DNA. (C) Trace (solid) and retrace (dashed) height profiles taken along straight lines as indicated in B, closely following the backbone of the four plasmid scans and averaged over a 5-pixel (~0.5) width.
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