Molecular Architecture of the Inositol Phosphatase Siw14
Molecular Architecture of the Inositol Phosphatase Siw14
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DOI：
10.1021/acs.biochem.8b01044
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发表时间：
2019-02-12
期刊：
影响因子：
2.9
通讯作者：
Cingolani, Gino
中科院分区：
文献类型：
--
作者：
Florio, Tyler J.;Lokareddy, Ravi K.;Cingolani, Gino
Siw 14是最近发现的一种肌醇磷酸酶，它参与抑制酿酒酵母中朊病毒的繁殖。在本文中，我们使用混合结构的方法来破译Siw 14分子结构。我们发现该蛋白在溶液中以类似于140埃长度的细长单体存在，含有酸性N端结构域和碱性C端双特异性磷酸酶（DSP）结构域，结构上类似于糖原磷酸酶laforin。这两个结构域通过蛋白酶敏感性接头连接，并且在体外不相互作用。Siw 14-DSP的晶体结构揭示了高度碱性的磷酸盐结合环和类似于10埃深的底物结合裂缝，其演变为使焦磷酸盐部分去磷酸化。从溶液，晶体学，生物化学和建模数据产生的全长磷酸酶的假原子模型揭示了有趣的两性离子性质的Siw 14，我们假设可能发挥作用，在歧视带负电荷的肌醇磷酸。
Siw14 is a recently discovered inositol phosphatase implicated in suppressing prion propagation in Saccharomyces cerevisiae. In this paper, we used hybrid structural methods to decipher Siw14 molecular architecture. We found the protein exists in solution as an elongated monomer that is similar to 140 angstrom in length, containing an acidic N-terminal domain and a basic C-terminal dual-specificity phosphatase (DSP) domain, structurally similar to the glycogen phosphatase laforin. The two domains are connected by a protease susceptible linker and do not interact in vitro. The crystal structure of Siw14-DSP reveals a highly basic phosphate-binding loop and an similar to 10 angstrom deep substrate-binding crevice that evolved to dephosphorylate pyro-phosphate moieties. A pseudoatomic model of the full-length phosphatase generated from solution, crystallographic, biochemical, and modeling data sheds light on the interesting zwitterionic nature of Siw14, which we hypothesized may play a role in discriminating negatively charged inositol phosphates.