1LRO

Aquifex aeolicus KDO8P synthase H185G mutant in complex with PEP and Cadmium

1LRO の概要

• エントリーDOI: 10.2210/pdb1lro/pdb
• 関連するPDBエントリー: 1FWW 1LRN 1LRQ
• 分子名称: KDO-8-phosphate synthetase, PHOSPHATE ION, CADMIUM ION, ... (5 entities in total)
• 機能のキーワード: kdo8ps, kdo8p, kdo, lyase
• 由来する生物種: Aquifex aeolicus
• 細胞内の位置: Cytoplasm : O66496
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 60137.47

構造登録者

Wang, J.,Duewel, H.S.,Stuckey, J.A.,Woodard, R.W.,Gatti, D.L. (登録日: 2002-05-15, 公開日: 2002-11-27, 最終更新日: 2024-02-14)

主引用文献

Wang, J.,Duewel, H.S.,Stuckey, J.A.,Woodard, R.W.,Gatti, D.L.
Function of His185 in Aquifex aeolicus 3-Deoxy-D-manno-octulosonate 8-Phosphate Synthase
J.Mol.Biol., 324:205-214, 2002

PubMed Abstract: Aquifex aeolicus 3-deoxy-D-manno-octulosonate 8-phosphate synthase (KDO8PS) catalyzes the condensation of arabinose 5-phosphate (A5P) and phosphoenolpyruvate (PEP) by favoring the activation of a water molecule coordinated to the active-site metal ion. Cys11, His185, Glu222 and Asp233 are the other metal ligands. Wild-type KDO8PS is purified with Zn(2+) or Fe(2+) in the active site, but maximal activity in vitro is achieved when the endogenous metal is replaced with Cd(2+). The H185G enzyme retains 8% of the wild-type activity. ICP mass spectrometry analysis indicates that loss of His185 decreases the enzyme affinity for Fe(2+), but not for Zn(2+). However, maximal activity is again achieved by substitution of the endogenous metal with Cd(2+). We have determined the X-ray structures of the Cd(2+) H185G enzyme in its substrate-free form, and in complex with PEP, and PEP plus A5P. These structures show a normal amount of Cd(2+) bound, suggesting that coordination by His185 is not essential to retain Cd(2+) in the active site. Nonetheless, there are significant changes in the coordination sphere of Cd(2+) with respect to the wild-type enzyme, as the carboxylate moiety of PEP binds directly to the metal ion and replaces water and His185 as ligands. These observations indicate that the primary function of His185 in A.aeolicus KDO8PS is to orient PEP in the active site of the enzyme in such a way that a water molecule on the sinister (si) side of PEP can be activated by direct coordination to the metal ion.

PubMed: 12441100
DOI: 10.1016/S0022-2836(02)01096-3

実験手法

X-RAY DIFFRACTION (1.8 Å)