Structure of 2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolase from Pseudomonas putida
Structure of 2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolase from Pseudomonas putida
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DOI：
10.1107/s0907444903013192
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发表时间：
2003-08-01
影响因子：
2.2
通讯作者：
Arni, RK
中科院分区：
文献类型：
--
作者：
Bell, BJ;Watanabe, L;Arni, RK
恶臭假单胞菌的2-酮-3-脱氧-6-磷酸葡萄糖酸（KDPG）醛缩酶是Entner-Doudoroff途径中的关键酶，通过I类希夫碱机制催化KDPG的切割。该酶的晶体结构已细化至晶体学残余R = 17.1%（无R = 21.4%）。N-末端螺旋覆盖（β α）（8）-桶的环面的一侧，活性位点位于桶的相对羧基侧。形成席夫碱的Lys 145由一个硫酸根（或磷酸根）离子和两个溶剂水分子配位。稳定三聚体的相互作用主要是疏水性的，除了一个分子的Glu 132 OE 1和一个等价分子的Thr 129 OG 1之间形成的环状排列键。除了N-末端螺旋外，恶臭假单胞菌的KDPG醛缩酶的结构与大肠杆菌的同源酶的结构非常相似。
2-Keto-3-deoxy-6-phosphogluconate (KDPG) aldolase from Pseudomonas putida is a key enzyme in the Entner-Doudoroff pathway which catalyses the cleavage of KDPG via a class I Schiff-base mechanism. The crystal structure of this enzyme has been refined to a crystallographic residual R = 17.1% (R-free = 21.4%). The N-terminal helix caps one side of the torus of the (betaalpha)(8)-barrel and the active site is located on the opposite, carboxylic side of the barrel. The Schiff-base-forming Lys145 is coordinated by a sulfate (or phosphate) ion and two solvent water molecules. The interactions that stabilize the trimer are predominantly hydrophobic, with the exception of the cyclically permuted bonds formed between Glu132 OE1 of one molecule and Thr129 OG1 of a symmetry-equivalent molecule. Except for the N-terminal helix, the structure of KDPG aldolase from P. putida closely resembles the structure of the homologous enzyme from Escherichia coli.