2IMF

2-Hydroxychromene-2-carboxylate Isomerase: a Kappa Class Glutathione-S-Transferase from Pseudomonas putida

2IMF の概要

• エントリーDOI: 10.2210/pdb2imf/pdb
• 関連するPDBエントリー: 1R4W 2IMD 2IMF
• 分子名称: 2-hydroxychromene-2-carboxylate isomerase, PHOSPHATE ION, GLUTATHIONE, ... (6 entities in total)
• 機能のキーワード: isomerase, glutathione, kgst, kappa gst, transferase
• 由来する生物種: Pseudomonas putida
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 24102.92

構造登録者

Thompson, L.C.,Ladner, J.E.,Codreanu, S.G.,Harp, J.,Gilliland, G.L.,Armstrong, R.N. (登録日: 2006-10-04, 公開日: 2007-06-12, 最終更新日: 2024-02-21)

主引用文献

Thompson, L.C.,Ladner, J.E.,Codreanu, S.G.,Harp, J.,Gilliland, G.L.,Armstrong, R.N.
2-Hydroxychromene-2-carboxylic acid isomerase: a kappa class glutathione transferase from Pseudomonas putida.
Biochemistry, 46:6710-6722, 2007

PubMed Abstract: The enzyme 2-hydroxychromene-2-carboxylic acid (HCCA) isomerase catalyzes the glutathione (GSH)-dependent interconversion (Keq = 1.5) of HCCA and trans-o-hydroxybenzylidene pyruvic acid (tHBPA) in the naphthalene catabolic pathway of Pseudomonas putida. The dimeric protein binds one molecule of GSH very tightly (Kd approximately 5 nM) and a second molecule of GSH with much lower affinity (Kd approximately 2 to 11 microM). The enzyme is unstable in the absence of GSH. The turnover number in the forward direction (47 s(-1) at 25 degrees C) greatly exceeds off rates for GSH (koff approximately 10(-3) to 10(-2) s(-1) at 10 degrees C), suggesting that GSH acts as a tightly bound cofactor in the reaction. The crystal structure of the enzyme at 1.7 A resolution reveals that the isomerase is closely related to class kappa GSH transferases. Diffraction quality crystals could only be obtained in the presence of GSH and HCCA/tHBPA. Clear electron density is seen for GSH. Electron density for the organic substrates is located near the GSH and is best modeled to include both HCCA and tHBPA at occupancies of 0.5 for each. Although there is no electron density connecting the sulfur of GSH to the organic substrates, the sulfur is located very close (2.78 A) to C7 of HCCA. Taken together, the results suggest that the isomerization reaction involves a short-lived covalent adduct between the sulfur of GSH and C7 of the substrate.

PubMed: 17508726
DOI: 10.1021/bi700356u

実験手法

X-RAY DIFFRACTION (1.3 Å)