2ADE

Crystal structure of fructan 1-exohydrolase IIa from Cichorium intybus in complex with fructose

2ADE の概要

• エントリーDOI: 10.2210/pdb2ade/pdb
• 関連するPDBエントリー: 2ADD 2ADE 2AEZ
• 分子名称: fructan 1-exohydrolase IIa, alpha-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (5 entities in total)
• 機能のキーワード: five fold beta propeller, hydrolase
• 由来する生物種: Cichorium intybus (chicory)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 62307.06

構造登録者

Verhaest, M.,Le Roy, K.,De Ranter, C.J.,Van Laere, A.,Van den Ende, W.,Rabijns, A. (登録日: 2005-07-20, 公開日: 2006-08-29, 最終更新日: 2024-11-20)

主引用文献

Verhaest, M.,Lammens, W.,Le Roy, K.,De Ranter, C.J.,Van Laere, A.,Rabijns, A.,Van den Ende, W.
Insights into the fine architecture of the active site of chicory fructan 1-exohydrolase: 1-kestose as substrate vs sucrose as inhibitor.
New Phytol, 174:90-100, 2007

PubMed Abstract: * Invertases and fructan exohydrolases (FEHs) fulfil important physiological functions in plants. Sucrose is the typical substrate for invertases and bacterial levansucrases but not for plant FEHs, which are usually inhibited by sucrose. * Here we report on complexes between chicory (Cichorium intybus) 1-FEH IIa with the substrate 1-kestose and the inhibitors sucrose, fructose and 2,5 dideoxy-2,5-imino-D-mannitol. Comparisons with other family GH32 and 68 enzyme-substrate complexes revealed that sucrose can bind as a substrate (invertase/levansucrase) or as an inhibitor (1-FEH IIa). * Sucrose acts as inhibitor because the O2 of the glucose moiety forms an H-linkage with the acid-base catalyst E201, inhibiting catalysis. By contrast, the homologous O3 of the internal fructose in the substrate 1-kestose forms an intramolecular H-linkage and does not interfere with the catalytic process. Mutagenesis showed that W82 and S101 are important for binding sucrose as inhibitor. * The physiological implications of the essential differences in the active sites of FEHs and invertases/levansucrases are discussed. Sucrose-inhibited FEHs show a K(i) (inhibition constant) well below physiological sucrose concentrations and could be rapidly activated under carbon deprivation.

PubMed: 17335500
DOI: 10.1111/j.1469-8137.2007.01988.x

実験手法

X-RAY DIFFRACTION (2.65 Å)