a, Fitting of the REC1 domain, with density of REC1220-354 from focused classification shown in grey mesh. A representative α-helix from the REC1 domain is shown in detail on the right. b, Secondary structure prediction of REC1220-354 using PSIPRED. c, Fitting of the WED domain. d, Fitting of the RuvC domain. e, Fitting of the REC2 domain. f, Fitting of the Nuc domain. g, Fitting of nucleic acids to the corresponding cryo-EM map, with details of a segment shown as indicated on the right. The atomic models are shown in stick with crRNA and tracrRNA regions colored in orange and yellow, respectively. h, Detailed interactions between scaffolding duplex 1 and Cas12g. Cryo-EM density map is shown in mesh.