1ZAI

Fructose-1,6-bisphosphate Schiff base intermediate in FBP aldolase from rabbit muscle

1ZAI の概要

• エントリーDOI: 10.2210/pdb1zai/pdb
• 関連するPDBエントリー: 1ZAH 1ZAJ 1ZAL
• 分子名称: Fructose-bisphosphate aldolase A, 1,6-FRUCTOSE DIPHOSPHATE (LINEAR FORM) (3 entities in total)
• 機能のキーワード: aldolase, substrate, schiff base intermediate, lyase
• 由来する生物種: Oryctolagus cuniculus (rabbit)
• 細胞内の位置: Cytoplasm, myofibril, sarcomere, I band : P00883
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 158415.15

構造登録者

St-Jean, M.,Lafrance-Vanasse, J.,Liotard, B.,Sygusch, J. (登録日: 2005-04-06, 公開日: 2005-05-10, 最終更新日: 2024-11-20)

主引用文献

St-Jean, M.,Lafrance-Vanasse, J.,Liotard, B.,Sygusch, J.
High Resolution Reaction Intermediates of Rabbit Muscle Fructose-1,6-bisphosphate Aldolase: substrate cleavage and induced fit.
J.Biol.Chem., 280:27262-27270, 2005

PubMed Abstract: Crystal structures were determined to 1.8 A resolution of the glycolytic enzyme fructose-1,6-bis(phosphate) aldolase trapped in complex with its substrate and a competitive inhibitor, mannitol-1,6-bis(phosphate). The enzyme substrate complex corresponded to the postulated Schiff base intermediate and has reaction geometry consistent with incipient C3-C4 bond cleavage catalyzed Glu-187, which is adjacent by to the Schiff base forming Lys-229. Atom arrangement about the cleaved bond in the reaction intermediate mimics a pericyclic transition state occurring in nonenzymatic aldol condensations. Lys-146 hydrogen-bonds the substrate C4 hydroxyl and assists substrate cleavage by stabilizing the developing negative charge on the C4 hydroxyl during proton abstraction. Mannitol-1,6-bis(phosphate) forms a noncovalent complex in the active site whose binding geometry mimics the covalent carbinolamine precursor. Glu-187 hydrogen-bonds the C2 hydroxyl of the inhibitor in the enzyme complex, substantiating a proton transfer role by Glu-187 in catalyzing the conversion of the carbinolamine intermediate to Schiff base. Modeling of the acyclic substrate configuration into the active site shows Glu-187, in acid form, hydrogen-bonding both substrate C2 carbonyl and C4 hydroxyl, thereby aligning the substrate ketose for nucleophilic attack by Lys-229. The multifunctional role of Glu-187 epitomizes a canonical mechanistic feature conserved in Schiff base-forming aldolases catalyzing carbohydrate metabolism. Trapping of tagatose-1,6-bis(phosphate), a diastereoisomer of fructose 1,6-bis(phosphate), displayed stereospecific discrimination and reduced ketohexose binding specificity. Each ligand induces homologous conformational changes in two adjacent alpha-helical regions that promote phosphate binding in the active site.

PubMed: 15870069
DOI: 10.1074/jbc.M502413200

実験手法

X-RAY DIFFRACTION (1.76 Å)