6X11

Observing a ring-cleaving dioxygenase in action through a crystalline lens - an enol tautomer of ACMS monodentately bound structure

6X11 の概要

• エントリーDOI: 10.2210/pdb6x11/pdb
• 分子名称: 3-hydroxyanthranilate 3,4-dioxygenase, 2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL, FE (II) ION, ... (5 entities in total)
• 機能のキーワード: in crystallo reaction, extradiol dioxygenase, nad+ biosynthesis, intermediate, oxidoreductase
• 由来する生物種: Cupriavidus metallidurans (strain ATCC 43123 / DSM 2839 / NBRC 102507 / CH34)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 23009.34

構造登録者

Wang, Y.,Liu, F.,Yang, Y.,Liu, A. (登録日: 2020-05-17, 公開日: 2020-07-29, 最終更新日: 2023-10-18)

主引用文献

Wang, Y.,Liu, K.F.,Yang, Y.,Davis, I.,Liu, A.
Observing 3-hydroxyanthranilate-3,4-dioxygenase in action through a crystalline lens.
Proc.Natl.Acad.Sci.USA, 117:19720-19730, 2020

PubMed Abstract: The synthesis of quinolinic acid from tryptophan is a critical step in the de novo biosynthesis of nicotinamide adenine dinucleotide (NAD) in mammals. Herein, the nonheme iron-based 3-hydroxyanthranilate-3,4-dioxygenase responsible for quinolinic acid production was studied by performing time-resolved reactions monitored by UV-vis microspectroscopy, electron paramagnetic resonance (EPR) spectroscopy, and X-ray crystallography. Seven catalytic intermediates were kinetically and structurally resolved in the crystalline state, and each accompanies protein conformational changes at the active site. Among them, a monooxygenated, seven-membered lactone intermediate as a monodentate ligand of the iron center at 1.59-Å resolution was captured, which presumably corresponds to a substrate-based radical species observed by EPR using a slurry of small-sized single crystals. Other structural snapshots determined at around 2.0-Å resolution include monodentate and subsequently bidentate coordinated substrate, superoxo, alkylperoxo, and two metal-bound enol tautomers of the unstable dioxygenase product. These results reveal a detailed stepwise O-atom transfer dioxygenase mechanism along with potential isomerization activity that fine-tunes product profiling and affects the production of quinolinic acid at a junction of the metabolic pathway.

PubMed: 32732435
DOI: 10.1073/pnas.2005327117

実験手法

X-RAY DIFFRACTION (2.097 Å)