Patent
This invention pertains to mutant Cas9 nucleic acids and proteins for use in CRISPR/Cas endonuclease systems, and their methods of use. In particular, the invention pertains to an isolated mutant Cas9 protein, wherein the isolated mutant Cas9 protein is active in a CRISPR/Cas endonuclease system, wherein the CRISPR/Cas endonuclease system displays reduced off-target editing activity and maintained on-target editing activity relative to a wild-type CRISPR/Cas endonuclease system. The invention also includes isolated nucleic acids encoding mutant Cas9 proteins, ribonucleoprotein complexes and CRSPR/Cas endonuclease systems having mutant Cas9 proteins that display reduced off-target editing activity and maintained on-target editing activity relative to a wild-type CRISPR/Cas endonuclease system.
1. An isolated nucleic acid encoding a mutant Cas9 protein selected from the group consisting of
(a) a single substitution mutation introduced into the WT-Cas9 protein of SEQ ID NO:5 selected from the following positions: N690, F682, K684 and D686; or
(b) a double substitution mutation introduced into the WT-Cas9 protein of SEQ ID NO:5 selected from two of following positions: N690, F682, L683, K684 and D686; or
(c) a double substitution mutation introduced into the WT-Cas9 protein of SEQ ID NO:5 comprising any one of following positions: N690, F682, L683, K684 and D686 in combination with any one of the following positions: R494, N522, N588, N612, T657, S663, R691, N692, S730, T740, R765, T770, N776, R778, R783, S793, N803, S845, N854, S872 and R925.
2. The isolated nucleic acid of claim 1 , wherein the encoded mutant Cas9 protein is selected from the group consisting of SEQ ID NO: 143, 145, 147, and 150.
3. An isolated nucleic acid encoding a mutant Cas9 protein selected from the group consisting of SEQ ID NO: 141-143, 145-151, 154, 155, and 157-168.