2EB4

Crystal structure of apo-HpcG

2EB4 の概要

• エントリーDOI: 10.2210/pdb2eb4/pdb
• 関連するPDBエントリー: 2EB5 2EB6
• 分子名称: 2-oxo-hept-3-ene-1,7-dioate hydratase, THIOCYANATE ION, SODIUM ION, ... (4 entities in total)
• 機能のキーワード: lyase, hydratase
• 由来する生物種: Escherichia coli
• タンパク質・核酸の鎖数: 5
• 化学式量合計: 149391.83

構造登録者

Izumi, A.,Rea, D.,Adachi, T.,Unzai, S.,Park, S.Y.,Roper, D.I.,Tame, J.R.H. (登録日: 2007-02-07, 公開日: 2007-07-17, 最終更新日: 2024-03-13)

主引用文献

Izumi, A.,Rea, D.,Adachi, T.,Unzai, S.,Park, S.Y.,Roper, D.I.,Tame, J.R.H.
Structure and Mechanism of HpcG, a Hydratase in the Homoprotocatechuate Degradation Pathway of Escherichia coli
J.Mol.Biol., 370:899-911, 2007

PubMed Abstract: HpcG catalyses the hydration of a carbon-carbon double bond without the aid of any cofactor other than a simple divalent metal ion such as Mg(2+). Since the substrate has a nearby carbonyl group, it is believed that it first isomerises to form a pair of conjugated double bonds in the enol tautomer before Michael addition of water. Previous chemical studies of the reaction, and that of the related enzyme MhpD, have failed to provide a clear picture of the mechanism. The substrate itself is unstable, preventing co-crystallisation or soaking of crystals, but oxalate is a strong competitive inhibitor. We have solved the crystal structure of the protein in the apo form, and with magnesium and oxalate bound. Modelling substrate into the active site suggests the attacking water molecule is not part of the metal coordination shell, in contrast to a previous proposal. Our model suggests that geometrically strained cis isomer intermediates do not lie on the reaction pathway, and that separate groups are involved in the isomerisation and hydration steps.

PubMed: 17559873
DOI: 10.1016/j.jmb.2007.05.006

実験手法

X-RAY DIFFRACTION (1.6 Å)