Skip to main content
. Author manuscript; available in PMC: 2023 Mar 20.
Published in final edited form as: Mol Cell. 2023 Feb 16;83(5):746–758.e5. doi: 10.1016/j.molcel.2023.01.024

Figure 5. AcrIC4 occludes the PAM site but makes different Cascade contacts than AcrIF2.

Figure 5.

(A) 3.1 Å resolution cryoelectron structure of the type I-C Cascade bound to AcrIC4.

(B) AcrIC4 interacts with both Cas8c and Cas7c through a large network of non-specific interactions.

(C) AcrIC4 is entirely negatively charged and wedged between positively charged Cas8c and Cas7.6 surfaces.

(D) Structural superposition of the type I-C dsDNA-bound model shows severe clashing between PAM residues and AcrIC4.

(E) Overlay of the IF2 and IC4 binding sites demonstrates a partially overlapping interface at the PAM site.