Table 2 Properties of engineered CRRISPR-Cas9 variants

SpCas9 VRER

D1135V, G1218R, R1335E, T1337R of SpCas9 mutations

NGCG

Altered PAM variant; Bacterial-selection-based screening

[41, 60]

SpCas9 VQR

D1135V, R1335Q, T1337R of SpCas9 mutations

NGAN or NGNG

Altered PAM variant; Bacterial-selection-based screening

[41, 60]

SpCas9 EQR

D1135E, R1335Q, T1337R of SpCas9 mutations

NGAG

Altered PAM variant; Bacterial-selection-based screening

[61]

SpCas9-NG

R1335V, L1111R, D1135V, G1218R, E1219F, A1322R, T1337R of SpCas9 mutations

NG

Altered PAM variant

[62]

SpG

D1135L, S1136W, G1218K, E1219Q, R1335Q, T1337R of SpCas9 mutations

NGN

A near-PAMless variant

[43, 63]

SpRY

A61R, L1111R, N1317R, A1322R, R1333P introduced into SpG

NRN, NYN

A near-PAMless variant

[43, 63]

xCas9 3.7

E480K, E543D, E1219V, A262T, R324L, S409I, M694I of SpCas9 mutations

NG, GAA, GAT

Expanded PAM recognition range; Phage-assisted continuous evolution (PACE)

[25, 59]

SpCas9-HF1

N497A, R661A, Q695A, Q926A of SpCas9 mutations

NGG

Enhanced specificity

[64]

eSpCas9 (1.0)

K810A, K1003A, R1060A of SpCas9 mutations

NGG

Enhanced specificity; Structure-guided protein engineering

[65]

eSpCas9 (1.1)

K848A, K1003A, R1060A of SpCas9 mutations

NGG

Enhanced specificity; Structure-guided protein engineering

[65, 66]

evoCas9

M495V, Y515N, K526E, R661Q of SpCas9 mutations

NGG

Enhanced specificity; Yeast-based screening

[42]

HypaCas9

N692A, M694A, Q695A, H698A of SpCas9 mutations

NGG

Enhanced specificity

[67]

HiFi Cas9

single point mutation R691A of SpCas9

NGG

Enhanced specificity for ribonucleoprotein delivery

[68]

KKH SaCas9

E782K, N968K, R1015H of SaCas9 mutations

NNNRRT

Altered PAM variant

[69, 70]

SaCas-HF

R245A, N413A, N419A, R654A of SaCas9 mutations

NNGRRT

Enhanced specificity and genome-wide targeting accuracy

[69, 70]

efSaCas9

single point mutation N260D of SaCas9 variant Mut268

NNGRRT

Enhanced specificity; Human cells-based screening

[71, 72]

(HiFi-)Sc⁺⁺

Thr1227Lys, Arg701Ala mutations and loop sequence from S. anginosus introduced into ScCas9

NNG

Enhanced specificity and activity

[73, 74]