Fig. S1.

Protein sequence alignment of NEL domain homologs from Salmonella (SspH1, SspH2, and SlrP), Shigella (IpaH9.8), Rhizobium (NopM), Bradyrhizobium (Blr1904), Yersinia (y3397), and Pseudomonas (PSPTO_1492, Pfl01_4099) species. For each gene, the UniProt identifier is indicated in brackets. Sequences are shaded by similarity with a 50% identity cutoff, with residues grouped based on their side chain character using ALINE software (49). Sequence numbering for IpaH9.8 and SspH1 are shown above their respective sequences. A red star highlights the catalytic cysteine, and green triangles highlight conserved surface residues targeted for mutagenesis in this study.