Extended Data Fig. 6: Cryo-EM single particle reconstruction of the single-PAM prespacer bound GsuCas4/Cas1-Cas2.
From: Mechanism for Cas4-assisted directional spacer acquisition in CRISPR–Cas
a. Flow-chart of the cryo-EM single particle reconstruction process that led to the reconstruction of two major snapshots. Left: Asymmetrical PAM/Non-PAM prespacer bound Cas4/1-2 complex. Right: That of the sub complex lacking (Cas4/1)2 on the non-PAM side. b. Cryo-EM density of the two reconstructions colored according to local resolution (top); viewing direction distribution plot (middle); and FSC curves (bottom). c. Superposition of the PAM side and non-PAM side densities showing that Cas4 density is largely missing at the non-PAM side, and the non-PAM 3’-overhang is largely disordered. Only the first four nucleotides of the non-PAM 3′-overhang can be traced in the density, along a similar path as in the PAM-side.
