Fig 1.

(A) Pathways for the catabolism of phenylethylamine, tyramine, and dopamine. The first reaction is catalyzed by the periplasmic amine oxidase (TynA) and the second reaction by an NAD-linked dehydrogenase (FeaB). Where substituents at the 3 and 4 positions are hydrogen, the three compounds are phenylethylamine, phenylacetaldehyde, and phenylacetate. With a hydroxyl group at the 4 position, they are tyramine, 4-hydroxyphenylacetaldehyde, and 4-hydroxyphenylacetate. With hydroxyl groups at both the 3 and 4 positions, they are dopamine, 3,4-dihydroxyphenylacetaldehyde, and 3,4-dihydroxyphenylacetate. (B and C) Schematics of the organization of the feaR-feaB intergenic region (B) and the tynA regulatory region (C). Transcription start sites are indicated by bent arrows. Verified and predicted binding sites for regulatory proteins are shown: FeaR (open circles), CRP (filled circle), NAC (open triangle), PhoB (open square), and NsrR (filled square). For additional details and DNA sequences, see Fig. 2.