List of Cas9 variants developed to enhance specificity of sgRNA targeting
| Name | Modification | Note |
|---|---|---|
| Cas9n or D10A Cas9 nickase | D10A | Developed by targeted mutation to induce rare DSB from nucleotide nickase (38), its paired D10A usage has reduced off-target and increased efficiency (62) |
| SpCas9-HF | N497A, R661A, Q695A, Q926A | Alteration of amino acid at gDNA interacting domain increase specificity (57) based on structural data from Cas9/gDNA complex crystallization (59) |
| espCas9(1.0)/(1.1) | K810A/K848A, K1003A, R1060A | Modification of amino acid at interacting with noncomplementary DNA strand based on structural data from Cas9/gDNA complex crystallization (61) |
| HypaCas9 | N692A, M694A, Q695A, H698A | Alteration in REC3 domain, identified by single-molecule Förster resonance energy transfer experiments (68) |
| HifiCas9 | R691A | Identified by unbiased bacterial screening method (69) |
| evoCas9 | M495V, Y515N, K526E, R661Q | Yeast based screening of random mutation in the REC3 domain (70) |
| SniperCas9 | F5395, M763I, K890N | Directed evolution in a |
| xCas9-3.6 | E108G, S217A, A262T, S409I, E480K, E543D, M694I, E1219V | Phage assisted evolution to screen for Cas9 variants to diversify PAM sites. Those variants are also more specific to target sites (72) |
| xCas9-3.7 | A262T, R324L, S409I, E480K, E543D, M694I, E1219V |