Homologs of napA from Shewanella oneidensis MR-1
napA: periplasmic nitrate reductase (NCBI ptt file)
SEED: Periplasmic nitrate reductase precursor (EC 1.7.99.4)
KEGG: periplasmic nitrate reductase NapA
Top 100 hits from BLASTp (E < 0.01)
Or try PaperBLAST, fast.genomics, the ENIGMA genome browser, or the comparative fitness browser