The pleckstrin homology domain of phospholipase C-delta(1) binds with high affinity to phosphatidylinositol 4,5-bisphosphate in bilayer membranes
The pleckstrin homology domain of phospholipase C-delta(1) binds with high affinity to phosphatidylinositol 4,5-bisphosphate in bilayer membranes
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DOI：
10.1021/bi00049a039
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发表时间：
1995-12-12
期刊：
影响因子：
2.9
通讯作者：
Rebecchi, MJ
中科院分区：
文献类型：
--
作者：
Garcia, P;Gupta, R;Rebecchi, MJ
磷脂酶C-δ（1）（PLC-δ（1））的普列克底物蛋白同源（PH）结构域与磷脂膜中的磷脂酰肌醇4，5-二磷酸（PI（4，5）P-2）结合，其亲和力（K-α类似于10（6）M（-1））和特异性与天然酶相当。PLC-δ（1）及其PH结构域也以相当的亲和力和大约1：1的化学计量结合肌醇1，4，5-三磷酸，PI（4，5）P-2的极性头基。对应于PLC-δ（1）PH结构域的氨基酸30-43的肽含有几个预测结合PI（4，5）P-2的碱性残基，但结合较弱且对PI（4，5）P-2具有很小的特异性;因此分离的PH结构域的三级结构是高亲和力PI（4，5）P-2结合所需的。我们的PI（4，5）P-2结合结果支持了这样的假设，即完整的PH结构域，作为一个特异性的系链，将PLC-δ（1）引导到富含PI（4，5）P-2的膜上，并允许位于蛋白质其他位置的活性位点在该酶从膜表面解离之前水解多个底物分子。
The pleckstrin homology (PH) domain of phospholipase C-delta(1) (PLC-delta(1)) binds to phosphatidylinositol 4,5-bisphosphate (PI(4,5)P-2) in phospholipid membranes with an affinity (K-a similar to 10(6) M(-1)) and specificity comparable to those of the native enzyme. PLC-delta(1) and its PH domain also bind inositol 1,4,5-trisphosphate, the polar head group of PI(4,5)P-2, with comparable affinity and approximately 1:1 stoichiometry. A peptide corresponding to amino acids 30-43 of the PLC-delta(1) PH domain contains several basic residues predicted to bind PI(4,5)P-2, but binds weakly and with little specificity for PI(4,5)P-2; hence the tertiary structure of the isolated PH domain is required for high affinity PI(4,5)P-2 binding. Our PI(4,5)P-2 binding results support the hypothesis that the intact PH domain, serving as' a specific tether, directs PLC-delta(1) to membranes enriched in PI(4,5)P-2 and permits the active site, located elsewhere in the protein, to hydrolyze multiple substrate molecules before this enzyme dissociates from the membrane surface.