Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, PL-30239 Krakow, Poland.
Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, PL-30239 Krakow, Poland; Department of Crystal Chemistry and Crystal Physics, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, PL-30387 Krakow, Poland.
J Struct Biol. 2018 Jun;202(3):229-235. doi: 10.1016/j.jsb.2018.01.007. Epub 2018 Feb 14.
Thebaine 6-O-demethylase (T6ODM) from Papaver somniferum (opium poppy), which belongs to the non-heme 2-oxoglutarate/Fe(II)-dependent dioxygenases (ODD) family, is a key enzyme in the morphine biosynthesis pathway. Initially, T6ODM was characterized as an enzyme catalyzing O-demethylation of thebaine to neopinone and oripavine to morphinone. However, the substrate range of T6ODM was recently expanded to a number of various benzylisoquinoline alkaloids. Here, we present crystal structures of T6ODM in complexes with 2-oxoglutarate (T6ODM:2OG, PDB: 5O9W) and succinate (T6ODM:SIN, PDB: 5O7Y). Both metal and 2OG binding sites display similarity to other proteins from the ODD family, but T6ODM is characterized by an exceptionally large substrate binding cavity, whose volume can partially explain the promiscuity of this enzyme. Moreover, the size of the cavity allows for binding of multiple molecules at once, posing a question about the substrate-driven specificity of the enzyme.
蒂巴因 6-O-去甲基酶（T6ODM）来源于罂粟（鸦片罂粟），属于非血红素 2-酮戊二酸/Fe(II)-依赖性双加氧酶（ODD）家族，是吗啡生物合成途径中的关键酶。最初，T6ODM 被表征为一种酶，可催化蒂巴因的 O-去甲基化为那可丁酮和可待因酮为吗啡酮。然而，T6ODM 的底物范围最近已扩展到许多各种苄基异喹啉生物碱。在这里，我们展示了 T6ODM 与 2-酮戊二酸（T6ODM:2OG，PDB：5O9W）和琥珀酸（T6ODM:SIN，PDB：5O7Y）复合物的晶体结构。金属和 2OG 结合位点均与 ODD 家族的其他蛋白质相似，但 T6ODM 的特点是具有异常大的底物结合腔，其体积部分解释了该酶的混杂性。此外，腔的大小允许同时结合多个分子，这对酶的底物驱动特异性提出了一个问题。
