Methods and compositions for evolving base editors using phage-assisted continuous evolution (pace)

3-7. (canceled)

9-29. (canceled)

A cytidine deaminase comprising an amino acid sequence that is at least 80% identical to amino acid residues 2-208 of SEQ ID NO:

• 3, wherein the cytidine deaminase comprises one or more mutations selected from the group consisting of H10X1, F23X2, V75X3, K120X4, A123X5, C158X6, I193X7, I195X8, and V197X9 relative to SEQ ID NO:
• 3, or a corresponding mutation(s) in another cytidine deaminase, wherein X1, is any amino acid other than H, X2 is any amino acid other than F, X3 and X9 are any amino acid other than V, X4 is any amino acid other than K, X5 is any amino acid other than A, X6 is any amino acid other than C, and X7 and X8 are any amino acid other than I.

32-44. (canceled)

46-47. (canceled)

A cytidine deaminase comprising an amino acid sequence that is at least 80% identical to amino acid residues 3-229 of SEQ ID NO:

• 4, wherein the cytidine deaminase comprises one or more mutations selected from the group consisting of E4X1, H122X2, D124X3, R154X4, A165X5, P201X6, and F205X7 relative to SEQ ID NO:
• 4, or a corresponding mutation(s) in another cytidine deaminase, wherein X1 is any amino acid other than E, X2 is any amino acid other than H, X3 is any amino acid other than D, X4 is any amino acid other than R, X5 is any amino acid other than A, X6 is any amino acid other than P, and X7 is any amino acid other than F.

50-60. (canceled)

62-64. (canceled)

66-93. (canceled)

95-121. (canceled)

123-152. (canceled)

A fusion protein comprising a Cas9 domain, a uracil DNA glycosylase inhibitor (UGI) domain, and a C-intein, optionally wherein the fusion comprises an amino acid sequence that is at least 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to

• (SEQ ID NO:
• 138)
• MIKIATRKYLGKQNVYDIGVERDHNFALKNGFIASNC

154-175. (canceled)

A base editor comprising an amino acid sequence that is at least 80% identical to the one or more of the amino acid sequences selected from the group containing SEQ ID NO:

• 16, SEQ ID NO:
• 18, and SEQ ID NO:
• 20.