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Structural insights into the catalytic and substrate recognition mechanisms of bacterial l ‐arabinose 1‐dehydrogenase
Author(s) -
Watanabe Yasunori,
Iga Chinatsu,
Watanabe Yasuo,
Watanabe Seiya
Publication year - 2019
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.13424
Subject(s) - arabinose , dehydrogenase , nad+ kinase , biochemistry , oxidoreductase , stereochemistry , chemistry , catabolism , epimer , bacteria , xylose , enzyme , biology , fermentation , genetics
In Azospirillum brasilense , a gram‐negative nitrogen‐fixing bacterium, l ‐arabinose is converted to α‐ketoglutarate through a nonphosphorylative metabolic pathway. In the first step in the pathway, l ‐arabinose is oxidized to l ‐arabino‐γ‐lactone by NAD (P)‐dependent l ‐arabinose 1‐dehydrogenase (Ara DH ) belonging to the glucose‐fructose oxidoreductase/inositol dehydrogenase/rhizopine catabolism protein (Gfo/Idh/MocA) family. Here, we determined the crystal structures of apo‐ and NADP ‐bound Ara DH at 1.5 and 2.2 Å resolutions, respectively. A docking model of l ‐arabinose and NADP ‐bound Ara DH and structure‐based mutational analyses suggest that Lys91 or Asp169 serves as a catalytic base and that Glu147, His153, and Asn173 are responsible for substrate recognition. In particular, Asn173 may play a role in the discrimination between l ‐arabinose and d ‐xylose, the C4 epimer of l ‐arabinose.