Crystal structure of the ARF-GAP domain and ankyrin repeats of PYK2-associated protein β
Crystal structure of the ARF-GAP domain and ankyrin repeats of PYK2-associated protein β
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DOI：
10.1093/emboj/18.24.6890
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发表时间：
1999-12-15
期刊：
影响因子：
11.4
通讯作者：
Hubbard, SR
中科院分区：
文献类型：
--
作者：
Mandiyan, V;Andreev, J;Hubbard, SR
ADP核糖基化因子（ADP ribosylation factors，ARF）是GTP结合蛋白Pas超家族的成员，是真核生物中囊泡运输途径的重要组成部分。与Pas一样，ARF以GTP结合的形式存在，其活性持续时间由GTP酶激活蛋白（GTPase-activating proteins，GAP）控制，GAP协助ARF将GTP水解为GDP。PAP β是一种与非受体酪氨酸激酶PYK 2结合并被其磷酸化的蛋白质，含有几个模块化信号传导结构域，包括普列克底物蛋白同源结构域、SH 3结构域、锚蛋白重复序列和ARF-GAP结构域。ARF-GAP结构域的序列与其他GAP的序列没有可识别的相似性，并且包含特征性的Cys-X-2-Cys-X 16 -17-Cys-X-2-Cys moth。PAP β ARF-GAP结构域和C-末端锚蛋白重复序列的晶体结构已经在2.1埃分辨率下确定。ARF-GAP结构域包含一个中央三链β-折叠，两侧是五个α-螺旋，其中Zn 2+离子与富含半胱氨酸的蛾的四个半胱氨酸配位。还存在四个锚蛋白重复序列，其中前两个与ARF-GAP结构域形成广泛的界面。一个不变的精氨酸和几个附近的疏水残基是溶剂暴露的，并预测是与ARF相互作用的位点，这些残基的定点突变证实了它们在ARF-GAP活性中的重要性。
ADP ribosylation factors (ARFs), which are members of the Pas superfamily of GTP-binding proteins, are critical components of vesicular trafficking pathways in eukaryotes, Like Pas, ARFs are active in their GTP-bound form, and their duration of activity is controlled by GTPase-activating proteins (GAPs), which assist ARFs in hydrolyzing GTP to GDP. PAP beta, a protein that binds to and is phosphorylated by the non-receptor tyrosine kinase PYK2, contains several modular signaling domains including a pleckstrin homology domain, an SH3 domain, ankyrin repeats and an ARF-GAP domain. Sequences of ARF-GAP domains show no recognizable similarity to those of other GAPs, and contain a characteristic Cys-X-2-Cys-X16-17-Cys-X-2-Cys moth, The crystal structure of the PAP beta ARF-GAP domain and the C-terminal ankyrin repeats has been determined at 2.1 Angstrom resolution. The ARF-GAP domain comprises a central three-stranded beta-sheet flanked by five alpha-helices, with a Zn2+ ion coordinated by the four cysteines of the cysteine-rich moth, Four ankyrin repeats are also present, the first two of which form an extensive interface with the ARF-GAP domain. An invariant arginine and several nearby hydrophobic residues are solvent exposed and are predicted to be the site of interaction with ARFs, Site-directed mutagenesis of these residues confirms their importance in ARF-GAP activity.