1EX5

FRUCTOSE 1,6-BISPHOSPHATE ALDOLASE FROM RABBIT MUSCLE

1EX5 の概要

• エントリーDOI: 10.2210/pdb1ex5/pdb
• 関連するPDBエントリー: 1ADO 1EWD 1EWE 1EWG
• 分子名称: FRUCTOSE 1,6-BISPHOSPHATE ALDOLASE (2 entities in total)
• 機能のキーワード: aldolase, lyase(aldehyde), schiff base, glycolysis, 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: 156822.55

構造登録者

Maurady, A.,Sygusch, J. (登録日: 2000-04-25, 公開日: 2001-01-24, 最終更新日: 2024-02-07)

主引用文献

MAURADY, A.,ZDANOV, A.,De Moissac, D.,Beaudry, D.,SYGUSCH, J.
A conserved glutamate residue exhibits multifunctional catalytic roles in D-fructose-1,6-bisphosphate aldolases.
J.Biol.Chem., 277:9474-9483, 2002

PubMed Abstract: The aldolase catalytic cycle consists of a number of proton transfers that interconvert covalent enzyme intermediates. Glu-187 is a conserved amino acid that is located in the mammalian fructose-1,6-bisphosphate aldolase active site. Its central location, within hydrogen bonding distance of three other conserved active site residues: Lys-146, Glu-189, and Schiff base-forming Lys-229, makes it an ideal candidate for mediating proton transfers. Point mutations, Glu-187--> Gln, Ala, which would inhibit proton transfers significantly, compromise activity. Trapping of enzymatic intermediates in Glu-187 mutants defines a proton transfer role for Glu-187 in substrate cleavage and Schiff base formation. Structural data show that loss of Glu-187 negative charge results in hydrogen bond formation between Lys-146 and Lys-229 consistent with a basic pK(a) for Lys-229 in native enzyme and supporting nucleophilic activation of Lys-229 by Glu-187 during Schiff base formation. The crystal structures also substantiate Glu-187 and Glu-189 as present in ionized form in native enzyme, compatible with their role of catalyzing proton exchange with solvent as indicated from solvent isotope effects. The proton exchange mechanism ensures Glu-187 basicity throughout the catalytic cycle requisite for mediating proton transfer and electrostatic stabilization of ketamine intermediates. Glutamate general base catalysis is a recurrent evolutionary feature of Schiff base0forming aldolases.

PubMed: 11779856
DOI: 10.1074/jbc.M107600200

実験手法

X-RAY DIFFRACTION (2.2 Å)