Extended Data Fig. 10. Structural alignment of DddA with ssDNA-bound APOBEC3G.

a, Crystal structure of DddA (grey, PDB 6U08) complexed with DddI immunity protein (not shown). Positions of mutations common to the CCC- and GCC-specific evolutions are colored in purple. Additional mutations are colored according to Fig. 3c. DddA was split at G1397 (red) to generate T7-DdCBE for PANCE and PACE. b, DddA (PDB 6UO8, grey) was aligned to the catalytic domain of APOBEC3G (PDB 2KBO, red) complexed to its ssDNA 5’-CCA substrate (orange) using Pymol. The target C undergoing deamination by APOBEC3G is indicated as C₀. Reversion analysis on the DddA11 mutant indicated that A1341V, N1342S and E1370K are critical for expanding the targeting scope of DddA (see Fig. 3f). D317 (red) confers 5’-CC specificity in APOBEC3G and loop 3 controls the catalytic activity of the APOBEC3G.