Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime, 790-8566, Japan; Department of Bioscience, Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime, 790-8566, Japan; Center for Marine Environmental Studies (CMES), Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan.
Department of Bioscience, Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime, 790-8566, Japan.
Biochem Biophys Res Commun. 2022 May 14;604:14-21. doi: 10.1016/j.bbrc.2022.03.028. Epub 2022 Mar 8.
l-Arabinose 1-dehydrogenase (AraDH) catalyzes the NAD(P)-dependent oxidation of l-arabinose to L-arabinono-1,4-lactone in the non-phosphorylative l-arabinose pathway, and is classified into glucose-fructose oxidoreductase and short-chain dehydrogenase/reductase (SDR). We herein report the crystal structure of a SDR-type AraDH (from Herbaspirillum huttiense) for the first time. The interactions between Asp49 and the 2'- and 3'-hydroxyl groups of NAD were consistent with strict specificity for NAD. In a binding model for the substrate, Ser155 and Tyr168, highly conserved in the SDR superfamily, interacted with the C1 and/or C2 hydroxyl(s) of l-arabinose, whereas interactions between Asp107, Arg109, and Gln206 and the C2 and/or C3 hydroxyl(s) were unique to AraDH. Trp200 significantly contributed to the selectivities of the C4 hydroxyl and C6 methyl of substrates.
L-阿拉伯糖 1-脱氢酶（AraDH）在非磷酸化 L-阿拉伯糖途径中催化 NAD(P)依赖性氧化 L-阿拉伯糖为 L-阿拉伯糖-1,4-内酯，属于葡萄糖-果糖氧化还原酶和短链脱氢酶/还原酶（SDR）。本文首次报道了 SDR 型 AraDH（来自 Herbaspirillum huttiense）的晶体结构。Asp49 与 NAD 的 2'-和 3'-羟基之间的相互作用与 NAD 的严格特异性一致。在底物结合模型中，SDR 超家族中高度保守的 Ser155 和 Tyr168 与 L-阿拉伯糖的 C1 和/或 C2 羟基相互作用，而 Asp107、Arg109 和 Gln206 与 C2 和/或 C3 羟基之间的相互作用则是 AraDH 所特有的。Trp200 对底物的 C4 羟基和 C6 甲基的选择性有重要贡献。
