The first structure of pectate lyase belonging to polysaccharide lyase family 3
The first structure of pectate lyase belonging to polysaccharide lyase family 3
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DOI：
10.1107/s0907444901014482
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发表时间：
2001-12-01
影响因子：
2.2
通讯作者：
Yamane, T
中科院分区：
文献类型：
--
作者：
Akita, M;Suzuki, A;Yamane, T
用多重同晶置换（MIR）法测定了一种高碱性低分子量果胶酸裂解酶（Pel-15）的晶体结构，其分辨率为1.5埃。这是来自多糖裂解酶家族3的第一个果胶酸裂解酶结构。整体结构是一个简单的八个转角的右手平行β-螺旋结构域，其中一个长环从β-螺旋的一侧突出。Pel-15的低分子量源于缺乏在许多β-螺旋蛋白中发现的N-和C-末端延伸。虽然该结构在pH 6.7时有一个钙离子，但将pH升高至9.5会导致额外钙离子的结合。在pH 6.5和9.5结构中发现的共同钙离子似乎稳定了β-螺旋结构和长的突出环。单独在pH 9.5结构中发现的额外钙离子可以中和酸性底物。额外的钙离子周围的区域被认为与底物结合，因为该区域富含催化所需的带电氨基酸残基。
The crystal structure of a highly alkaline low molecular weight pectate lyase (Pel-15) was determined at 1.5 Angstrom resolution by the multiple isomorphous replacement (MIR) method. This is the first pectate lyase structure from polysaccharide lyase family 3. The overall structure is a simple eight-turn right-handed parallel beta -helix domain with one long loop protruding from one side of the beta -helix. The low molecular weight of Pel-15 derives from the lack of N- and C-terminal extensions that are found in many beta -helix proteins. Although the structure has one calcium ion at pH 6.7, raising the pH to 9.5 results in the binding of an additional calcium ion. The common calcium ion found in both the pH 6.5 and 9.5 structures seems to stabilize both the beta -helix structure and the long protruding loop. The additional calcium ion found in the pH 9.5 structure alone may neutralize the acidic substrate. The region around the additional calcium ion is thought to bind to the substrate, as this region is rich in charged amino-acid residues which are required in catalysis.