Supplementary Figure 1 Protein sequence alignment of TadA with related deaminases. (a) Conserved cytidine deaminase motif in S. aureus TadA (SaTadA), aligned with Homo sapiens APOBEC1 (HsApobec1) Mus musculus Activation-induced Cytidine Deaminase (MmAID), and E. coli nucleoside cytidine deaminase (CDA). Zinc coordinating residues are in aqua, the conserved glutamate required for proton transfer is in orange, and the conserved proline is in red. (b) Alignment of S. aureus TadA with other bacterial TadAs: Bacillus cereus TadA (BcTadA), Listeria monocytogenes TadA (LmTadA), Geobacter metallireducens (GmTadA), Aquifex aeolicus TadA (AaTadA), Oenococcus oeni TadA (OoTadA), Nitrosomonas europaea TadA (NeTadA), and Escherichia coli TadA (EcTadA). Secondary structure elements are indicated above the alignment with α-helices in red and β-sheets in yellow. Zinc coordinating residues are in aqua, the conserved glutamate required for proton transfer is in orange, conserved residues that interact with the bound RNA are in red. The black box is around the amino acid found TadAs at the position corresponding to S. aureus TadA Glu72, which is conserved in organisms bearing guanine at position 37 of tRNAArg2.