Table 1.

Major naturally occurring and genetically modified Cas enzymes used for genome editing.

Name	Cas	Resources	CRISPR/Cas	PAM*	PAM location	Reference
SpCas9	Cas9	Streptococcus pyogenes	Type II	NGG	3′	[16], [17]
SaCas9	Cas9	Streptococcus aureus	Type II	NNGRRT	3′	[130]
FnCas9	Cas9	Francisella Novicida	Type II	NGG	3′	[131]
NmCas9	Cas9	Neisseria meningitidis	Type II	NNNNGATT	3′	[132]
CjCas9	Cas9	Campylobacter jejuni	Type II	NNNNRYAC	3′	[133]
St1Cas9	Cas9	Streptococcus thermophilus	Type II	NNAGAAW	3′	[25], [26]
St1Cas9	Cas9	Streptococcus thermophilus	Type II	NGGNG	3′	[25], [26]
AsCas12a	Cas12a(cpf1)	Acidaminococcus ​sp.	Type II	TTTV	5′	[134]
LbCas12a	Cas12a(cpf1)	Lachnospiraceae bacterium	Type II	TTTV	5′	[134]
FnCas12a	Cas12a(cpf1)	Francisella Novicida	Type II	TTTN or YTN	5′	[134], [135]
LsCas13#	Cas13 (C2c2)	Leptotrichia shahii	Type VI			[23]
Cas14&	Cas14	Archaea				[24]
FnCas9 variant	Cas9	Modified FnCas9	Type II	YG	3′	[131]
Modified SpCas9	Cas9	Engineered SpCas9	Type II	NGA or NAG	3′	[136]
SaCas9-KKH	Cas9	Engineered SaCas9	Type II	NNNRRT	3′	[29]
SpCas9-HF	Cas9	Engineered SpCas9	Type II	NGG	3′	[137]
eSpCas9	Cas9	Engineered SpCas9	Type II	NGG	3′	[138]
SpCas9-NG	Cas9	Engineered SpCas9	Type II	NG	3′	[28]
xCas9	Cas9	Engineered SpCas9	Type II	NG	3′	[139]
Sniper-Cas9	Cas9	Engineered SpCas9	Type II	NGG	3′	[140]
evoCas9	Cas9	Mutated SpCas9	Type II	NGG	3′	[141]
HypaCas9	Cas9	Mutated SpCas9-HF	Type II	NGG	3′	[142]
Cas9-NRNH	Cas9	Engineered SpCas9	Type II	NRNH	3′	[143]
SpG	Cas9	Engineered SpCas9	Type II	NGN	3′	[31]
SpRY	Cas9	Engineered SpCas9	Type II	NRN or NYN	3′	[31]

* N is any nucleotide. R is A or G. H is A, C or T. Y is C or T. W is A or T. # Cas13 targets RNA sequences instead of DNA; $ Cas14 targets ssDNAs instead of dsDNAs, which doesnot require a PAM.