Multiple-sequence alignment of DsrR and IscA sequences. Highly conserved residues in both DsrR and IscA-like proteins are shaded gray. Residues conserved only in DsrR are shaded green. Cysteine residues characteristic for IscA-like proteins are shaded yellow. Avi, Allochromatium vinosum DSM 180; Thi, Thioalkalivibrio sp. HL-EbGR7; Beg, Beggiatoa sp. PS; Ves, “Candidatus Vesicomyosocius okutanii” HA; Rma, “Candidatus Ruthia magnifica” strain Cm; Unc, uncultured bacterium BAC13K9BAC; Tde, Thiobacillus denitrificans ATCC 25259; Eco, Escherichia coli K-12; Aae, Aquifex aeolicus VF5; Tel, Thermosynechococcus elongatus BP-1; Hsa, Homo sapiens.