Extended Data Fig. 6. RuvC loop in on-target SpCas9 structures.

a, On-target inactive Cas9 bound to dsDNA (PDB 4UN3)¹⁵. RuvC loop is missing between 1013–1029. b, On-target inactive (primed – HNH rearranged and adjacent to target strand scissile phosphate) Cas9 bound to dsDNA (PDB 5F9R)¹⁴. RuvC loop has been built primarily as alanine ‘stub’ residues, but electron density is very poor and diffuse for this region. c, On-target inactive Cas9 bound to dsDNA (PDB 4OO8)⁴³. RuvC loop is missing between 1017–1028. d, On-target active Cas9 bound to dsDNA in postcatalysis state¹⁸. RuvC loop is missing between 1001–1077. e, On-target active Cas9 bound to dsDNA in product state¹⁸. RuvC loop is missing between 1000–1075. In a–c, electron density is displayed as a grey surface, and in d, e cryo-EM density is shown as a grey surface. In all structures, missing residues are depicted as a red dashed line with the RuvC loop in b shown as magenta. Position of RuvC loop is denoted by a black dashed box in the left panel for each model.