Fig. 1. SPKK-related motifs help identify Ddd_Bc homologs with dsDNA deaminase activity.

a The red boxes mark the SPKK-related motif sequences in Burkholderia cenocepacia Ddd_Bc and Psammechinus miliaris Histone H2B.1. b The schematic of constructs for wild type Ddd_Bc (WT), Ddd_Bc with two SPKK-related motifs removed (Delta), and Delta rescued with AT-hook sequence (AT-Hook). c Quantification of the relative amounts of deamination product versus protein concentration from different protein constructs as shown in b. Associate gels are shown in Supplementary Fig. 1a. Shown are mean ± SD; n = 3 independent experiments. d Summary for the sequence features and the activity of candidate Ddd_Bc homologs. #1: Ordered by PSI-BLAST score, from high to low. #2: +, the C-terminal region has one SPKK-related motif; ++, two SPKK-related motifs; -, no SPKK-related motif. #3: *, activity comparable to Ddd_Bc; **, activity higher than Ddd_Bc; -, activity low or weak. Associated gels and quantifying results are shown in Supplementary Fig. 2a–j. e–g Probability sequence logo of the region flanking mutated cytosines from the genome of UNG-deficient E.coli overexpressing Ddd_Ss (e), Ddd_Fa (f), and Ddd_Bc (g). Source data are provided as a Source Data file.