Multiple sequence alignment of 5NSA 1,2-dioxygenase from Bradyrhizobium JS329, salicylate-1,2-dioxygenase from Pseudaminobacter salicylatoxidans BN12 (GenBank accession number AY323951.1), 1-hydroxy-2-naphthoic acid dioxygenase from Mycobacterium sp. CH1 (GenBank accession number ACN38281.1), gentisate 1,2-dioxygenase from Burkholderia multivorans CGD2M (GenBank accession number ZP_03569724.1), and gentisate 1,2-dioxygenase from Oligotropha carboxidovorans OM5 (GenBank accession number YP_002287389.1). The conserved histidine pair is present at positions 123 and 125. The alignment in the two ends was trimmed due to the absence of conserved sites. SA, salicylate; GA, gentisate; 5NSA, 5-nitrosalicylic acid; HNA, 1-hydroxy-2-naphthoic acid.