Engineered adenosine deaminases and base editors thereof

1. An adenosine deaminase, comprising an amino acid sequence having about 85% to about 99.5% sequence identity to SEQ ID NO: 1 and having an amino acid substitution at each of residues E168 and E169, relative to the sequence shown in SEQ ID NO: 1.

2. The adenosine deaminase according to claim 1 , wherein the amino acid sequence having about 85% to about 99.5% sequence identity to SEQ ID NO: 1 further includes an amino acid substitution at one or more residues selected from the group consisting of W23, Y36, P48, H51, L84, A106, D108, V109, K110, T111, D119, G122, H123, S146, F149, R152, H156, and K157, relative to the sequence SEQ ID NO: 1.

3. The adenosine deaminase according to claim 1 , wherein the amino acid sequence having about 85% to about 99.5% sequence identity to SEQ ID NO: 1 further includes an amino acid substitution at each one of the residues of W23, Y36, P48, H51, L84, A106, D108, V109, T111, D119, G122, H123, S146, F149, R152, H156, and K157, relative to the sequence SEQ ID NO: 1.

4. The adenosine deaminase according to claim 3 , wherein:

(a) the substitution at W23 is selected from the group consisting of W23R, W23K and 23H;

(b) the substitution at Y36 is selected from the group consisting of Y36L, Y36V, Y36I and Y36P;

(c) the substitution at P48 is P48A;

(d) the substitution at H51 is selected from the group consisting of H51L, H51V, H51I and H51P;

(e) the substitution at L84 is selected from the group consisting of L84F, L84W and L84Y;

(f) the substitution at A106 is selected from the group consisting of A106V, A106I, A106L and A106P;

(g) the substitution at D108 is D108N;

(h) the substitution at V109 is V109S;

(i) the substitution at T111 is selected from the group consisting of T111R, T111K and T111H;

(j) the substitution at D119 is selected from the group consisting of D119N, D119R and D119Q;

(k) the substitution at G122 is G122N;

(l) the substitution at H123 is H123Y;

(m) the substitution at S146 is S146C;

(n) the substitution at F149 is selected from the group consisting of F149Y and F149H;

(o) the substitution at R152 is R152P;

(p) the substitution at H156 is selected from the group consisting of H156F, H156W and H156Y;

(q) the substitution at K157 is K157N;

(r) the substitution at E168 is E168I; and

(s) the substitution at E169 is E169N.

5. The adenosine deaminase according to claim 4 , wherein the adenosine deaminase comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 2 to 10 or an amino acid sequence having at least about 95% sequence identity to the amino acid sequence of any of SEQ ID NOs: 2 to 10, with the proviso that the adenosine deaminase does not include the amino acid sequence shown in SEQ ID NO: 1.

6. The adenosine deaminase according to claim 5 , wherein the adenosine deaminase comprises:

(i) the amino acid sequence of SEQ ID NO: 2 or an amino acid sequence having at least about 95% sequence identity to the amino acid sequence shown in SEQ ID NO: 2; or

(ii) the amino acid sequence of SEQ ID NO: 6 or an amino acid sequence having at least about 95% sequence identity to SEQ ID NO: 6;

with the proviso that the adenosine deaminase does not include the amino acid sequence SEQ ID NO: 1.

7. The adenosine deaminase according to claim 1 , wherein the substitution at residue E168 is E168I and the substitution at residue E169 is E169N.

8. A base editor comprising an adenosine deaminase according to claim 1 , further comprising a cytidine deaminase domain.

9. A base editor comprising a first adenosine deaminase according to claim 1 , further comprising a second adenosine deaminase domain that is the same as or different from the first adenosine deaminase.

10. A base editor comprising an adenosine deaminase according to claim 1 , further comprising one or more nuclear localization sequences.

11. A base editor comprising an adenosine deaminase according to claim 1 , further comprising a programmable DNA binding protein domain selected from Cas9 or Cas12 protein domains.

12. The base editor according to claim 11 , wherein the programmable DNA binding protein domain is a dCas9 domain or an nCas9 domain.

13. The base editor according to claim 12 , wherein the base editor comprises an architecture selected from the group consisting of:

NH 2 -[NLS]-[MaTadA1.0]-[dCas9/nCas9]-[NLS]-COOH;

NH 2 -[NLS]-[dCas9/nCas9]-[MaTadA1.0]-[NLS]-COOH;

NH 2 -[NLS]-[MaTadA1.0-1]-[dCas9/nCas9]-[NLS]-COOH;

NH 2 -[NLS]-[dCas9/nCas9]-[MaTadA1.0-1]-[NLS]-COOH;

NH 2 -[NLS]-[MaTadA1.0-2]-[dCas9/nCas9]-[NLS]-COOH;

NH 2 -[NLS]-[dCas9/nCas9]-[MaTadA1.0-2]-[NLS]-COOH;

NH 2 -[NLS]-[MaTadA1.0-3]-[dCas9/nCas9]-[NLS]-COOH;

NH 2 -[NLS]-[dCas9/nCas9]-[MaTadA1.0-3]-[NLS]-COOH;

NH 2 -[NLS]-[MaTadA1.1]-[dCas9/nCas9]-[NLS]-COOH;

NH 2 -[NLS]-[dCas9/nCas9]-[MaTadA1.1]-[NLS]-COOH;

NH 2 -[NLS]-[MaTadA1.2]-[dCas9/nCas9]-[NLS]-COOH;

NH 2 -[NLS]-[dCas9/nCas9]-[MaTadA1.2]-[NLS]-COOH;

NH 2 -[NLS]-[MaTadA1.3]-[dCas9/nCas9]-[NLS]-COOH;

NH 2 -[NLS]-[dCas9/nCas9]-[MaTadA1.3]-[NLS]-COOH;

NH 2 -[NLS]-[MaTadA1.4]-[dCas9/nCas9]-[NLS]-COOH;

NH 2 -[NLS]-[dCas9/nCas9]-[MaTadA1.4]-[NLS]-COOH;

NH 2 -[NLS]-[MaTadA1.5]-[dCas9/nCas9]-[NLS]-COOH; and

NH 2 -[NLS]-[dCas9/nCas9]-[MaTadA1.5]-[NLS]-COOH.

14. A complex comprising the base editor according to claim 11 and a guide RNA, wherein the guide RNA is linked to the programmable DNA binding protein domain of the base editor.

15. A base editor comprising an adenosine deaminase according to claim 1 , wherein the base editor comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 46 to 48.

16. A polynucleotide encoding an adenosine deaminase comprising an amino acid sequence having about 85% to about 99.5% sequence identity to SEQ ID NO: 1 and having an amino acid substitution at each of residues E168 and E169, relative to the sequence SEQ ID NO: 1.

17. A vector comprising the polynucleotide according to claim 16 .

18. A pharmaceutical composition comprising the vector of claim 17 and a pharmaceutically acceptable carrier.

19. A cell comprising the vector according to claim 17 .

20. A pharmaceutical composition comprising the cell of claim 19 and a pharmaceutically acceptable carrier.

21. A pharmaceutical composition comprising a base editor comprising an adenosine deaminase according to claim 1 or a complex comprising the base editor comprising an adenosine deaminase according to claim 1 and a guide RNA; and a pharmaceutically acceptable carrier.