Novel active site in Escherichia coli fructose 1,6-bisphosphate aldolase
Novel active site in Escherichia coli fructose 1,6-bisphosphate aldolase
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DOI：
10.1038/nsb1096-856
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发表时间：
1996-10-01
期刊：
影响因子：
--
通讯作者：
Sygusch, J
中科院分区：
文献类型：
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作者：
Blom, NS;Tetreault, S;Sygusch, J
II类E的分子结构。大肠杆菌果糖1，6-二磷酸醛缩酶二聚体的测定达到1.6埃分辨率。亚基折叠对应于单个缠绕的α/β-桶，其中活性位点位于每个亚基的β-桶羧基侧。在每个亚基中有两个相互排斥的锌金属离子结合位点，相距3.2埃;排他性是由涉及螯合组氨酸残基的侧链旋转的构象转变介导的。在β-桶中心附近发现了K+和NH 4+激活剂的结合位点。虽然I类和II类醛缩酶催化相同的反应，但它们的活性位点不共享共同的氨基酸残基，结构上不相似，并且从序列比较来看似乎是进化上不同的。
The molecular architecture of the Class II E. coli fructose 1,6-bisphosphate aldolase dimer was determined to 1.6 Angstrom resolution. The subunit fold corresponds to a singly wound alpha/beta-barrel with an active site located on the beta-barret carboxyl side of each subunit. In each subunit there are two mutually exclusive zinc metal ion binding sites, 3.2 Angstrom apart; the exclusivity is mediated by a conformational transition involving side-chain rotations by chelating histidine residues. A binding site for K+ and NH4+ activators was found near the beta-barrel centre. Although Class I and Class II aldolases catalyse identical reactions, their active sites do not share common amino add residues, are structurally dissimilar, and from sequence comparisons appear to be evolutionary distinct.