3I63

Peroxide Bound Toluene 4-Monooxygenase

3I63 の概要

• エントリーDOI: 10.2210/pdb3i63/pdb
• 関連するPDBエントリー: 3i5j
• 分子名称: Toluene-4-monooxygenase system protein A, Toluene-4-monooxygenase system protein E, Toluene-4-monooxygenase system protein B, ... (7 entities in total)
• 機能のキーワード: peroxide, t4moh, diiron hydroxylase, monooxygenase, aromatic hydrocarbons catabolism, fad, flavoprotein, iron, oxidoreductase
• 由来する生物種: Pseudomonas mendocina; 詳細
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 118012.35

構造登録者

Bailey, L.J.,Fox, B.G. (登録日: 2009-07-06, 公開日: 2009-10-13, 最終更新日: 2024-02-21)

主引用文献

Bailey, L.J.,Fox, B.G.
Crystallographic and catalytic studies of the peroxide-shunt reaction in a diiron hydroxylase.
Biochemistry, 48:8932-8939, 2009

PubMed Abstract: A diiron hydroxylase reaction typically begins by combination of O2 with a diferrous center to form reactive intermediates capable of hydrocarbon hydroxylation. In this natural cycle, reducing equivalents are provided by specific interactions with electron transfer proteins. The biological process can be bypassed by combining H2O2 with a diferric center, i.e., peroxide-shunt catalysis. Here we show that toluene 4-monooxygenase has a peroxide-shunt reaction that is approximately 600-fold slower than catalysis driven by biological electron transfer. However, the toluene 4-monooxygenase hydroxylase-effector protein complex was stable in the presence of 300 mM H2O2, suggesting overall benign effects of the exogenous oxidant on active site structure and function. The X-ray structure of the toluene 4-monooxygenase hydroxylase-effector protein complex determined from crystals soaked in H2O2 revealed a bound diatomic molecule, assigned to a cis-mu-1,2-peroxo bridge. This peroxo species resides in an active site position adjacent to the hydrogen-bonding substructure established by effector protein binding and faces into the distal cavity where substrate must bind during regiospecific aromatic ring hydroxylation catalysis. These results provide a new structural benchmark for how activated intermediates may be formed and dispatched during diiron hydroxylase catalysis.

PubMed: 19705873
DOI: 10.1021/bi901150a

実験手法

X-RAY DIFFRACTION (2.09 Å)