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Publication Abstract from PubMed

The bacterium Pseudomonas sp. AP-3 is able to use the environmental pollutant 2-aminophenol as its sole source of carbon, nitrogen, and energy. Eight genes (amnA, B, C, D, E, F, G, and H) encoding 2-aminophenol metabolizing enzymes are clustered into a single operon. 2-Aminomuconic 6-semialdehyde dehydrogenase (AmnC), a member of the aldehyde dehydrogenase (ALDH) superfamily, is responsible for oxidizing 2-aminomuconic 6-semialdehyde to 2-aminomuconate. In contrast to many other members of the ALDH superfamily, the structural basis of the catalytic activity of AmnC remains elusive. Here, we present the crystal structure of AmnC, which displays a homotetrameric quaternary assembly that is directly involved in its enzymatic activity. The tetrameric state of AmnC in solution was also presented using small-angle X-ray scattering. The tetramerization of AmnC is mediated by the assembly of a protruding hydrophobic beta-strand motif and residues V121 and S123 located in the NAD(+) -binding domain of each subunit. Dimeric mutants of AmnC dramatically lose NAD(+) binding affinity and failed to oxidize the substrate analogue 2-hydroxymuconate-6-semialdehyde to alpha-hydroxymuconic acid, indicating that tetrameric assembly of AmnC is functional requirement.

The tetrameric assembly of 2-aminomuconic 6-semialdehyde dehydrogenase is a functional requirement of cofactor NAD(+) binding.,Shi Q, Chen Y, Li X, Dong H, Chen C, Zhong Z, Yang C, Liu G, Su D Environ Microbiol. 2021 Nov 22. doi: 10.1111/1462-2920.15840. PMID:34806815^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.