Figure 7. Model Illustrating Target Sequence Dependency for Cas9 Target Binding and Cleavage.

Following PAM sampling by the Cas9:sgRNA complex, only PAM-proximal sequences are required for Cas9:sgRNA:target nucleation and are sufficient for complex formation [11]. Our study indicates that PAM-distal complementarity with the sgRNA (and a minimum sgRNA guide length of 17 nucleotides) is required to engage Cas9 target cleavage.