Cas9 nuclease can form ribonucleoprotein (RNP) complex with the single guide RNA (sgRNA) component of the CRISPR/Cas9 system, inducing site-specific DNA double-stranded breaks. The PAM sequence is NGG.

dCas9 protein is a ribozyme deficient Cas9 protein, which does not have sgRNA guided DNA strand cleavage activity, but retains target DNA binding activity, regulating the gene expression.

AapCas12b is an RNA-mediated endonuclease that binds to and cleaves specific sites of target DNA under the guidance of single-stranded guide RNA.

spCas9-NG is an RNA-mediated nuclease, which can catalyze the specific site cleavage of double-stranded DNA. It can recognize the NG PAM sequence.

When LwCas13a recognizes and cleaves the target RNA under the guidance of guide RNA, its "accessory cleavage" activity is activated, which can efficiently cleave non-specific single-stranded RNA (ssRNA) in the reaction system.

SpRYCas9 is an RNA-mediated nuclease, which can catalyze the specific site cleavage of double-stranded DNA. It can recognize the NNN (NRN > NYN) PAM sequence, which almost gets rid of the restriction of the PAM.

LbaCas12a (Cpf1) has a RuvC endonuclease domain similar to Cas9 but does not have the HNH endonuclease domain. LbaCas12a is not only smaller than Cas9, but also requires a smaller RNA (nearly half of Cas9's total sgRNA), which is very helpful for genome editing.

Compared with other Cas proteins, the molecular weight of Cas14 protein is generally smaller (400-700aa). Similar to Cas12, Cas14a1 can also bind the target nucleic acid and activate its ssDNA trans cleavage activity.