A structural basis for lithium and substrate binding of an inositide phosphatase.
A structural basis for lithium and substrate binding of an inositide phosphatase.
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DOI：
10.1074/jbc.ra120.014057
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发表时间：
2021-01
期刊：
影响因子：
--
通讯作者：
York JD
中科院分区：
文献类型：
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作者：
Dollins DE;Xiong JP;Endo-Streeter S;Anderson DE;Bansal VS;Ponder JW;Ren Y;York JD
肌醇多磷酸1-磷酸酶（INPP 1）是由保守的三维核心结构定义的金属依赖性/锂抑制性磷酸单酯酶蛋白家族的原型成员。该家族中的酶在不同的途径中起作用，包括肌醇信号传导、硫异生和硫同化。使用结构和生物化学研究，我们报告的影响基板和锂的金属结合位点的网络内的催化中心INPP 1。我们发现，锂优先占据一个关键的网站参与金属活化只有当底物或产品添加。一个保守的残基，选择性地协调假定的锂结合位点的突变结果在一个戏剧性的100倍的抑制常数减少相比，野生型。此外，我们报告INPP 1/肌醇1，4-二磷酸复合物，阐明了酶活性位点的关键特征。我们的研究结果提供了深入了解的结构基础，无竞争力的锂抑制和底物识别，并定义了一个序列基序的调节磷酸酶家族内的金属结合。
Inositol polyphosphate 1-phosphatase (INPP1) is a prototype member of metal-dependent/lithium-inhibited phosphomonoesterase protein family defined by a conserved three-dimensional core structure. Enzymes within this family function in distinct pathways including inositide signaling, gluconeogenesis, and sulfur assimilation. Using structural and biochemical studies, we report the effect of substrate and lithium on a network of metal binding sites within the catalytic center of INPP1. We find that lithium preferentially occupies a key site involved in metal-activation only when substrate or product is added. Mutation of a conserved residue that selectively coordinates the putative lithium-binding site results in a dramatic 100-fold reduction in the inhibitory constant as compared with wild-type. Furthermore, we report the INPP1/inositol 1,4-bisphosphate complex which illuminates key features of the enzyme active site. Our results provide insights into a structural basis for uncompetitive lithium inhibition and substrate recognition and define a sequence motif for metal binding within this family of regulatory phosphatases.