Fig. 4: Scanning-focused refinement.
From: Revealing the structures of megadalton-scale DNA complexes with nucleotide resolution
a Left: exemplary region of interest in the 4 × 4 domain in the Twisttower cryo-EM map. Right: same region, after two-body refinement using the two bodies indicated in the middle. b Schematic illustration of the iterative application of the procedure in (a) over the entire object. Bottom: Frankenstein map, created by combining the focal elements. c–f Left to right: arrows give examples of high-resolution features revealed after scanning-focused refinement: single-strand phosphate backbone bond, double-strand phosphate backbone bond, depression at a strand-break site, peripheral single-strand crossovers, and density from poly-T tails at a helical interface.
