Structural Basis for the Interaction between the Potato Virus X Resistance Protein (Rx) and Its Cofactor Ran GTPase-activating Protein 2 (RanGAP2)
Structural Basis for the Interaction between the Potato Virus X Resistance Protein (Rx) and Its Cofactor Ran GTPase-activating Protein 2 (RanGAP2)
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DOI：
10.1074/jbc.m113.517417
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发表时间：
2013-12-13
影响因子：
4.8
通讯作者：
Chai, Jijie
中科院分区：
文献类型：
--
作者：
Hao, Wei;Collier, Sarah M.;Chai, Jijie
背景：马铃薯抗病蛋白Rx与RanGAP2的互作对病毒抗性具有重要意义。结果：确定了Rx和RanGAP2 n端结构的配合物的晶体结构。结论：两种蛋白主要通过疏水相互作用结合。意义：这项工作揭示了参与分子内和分子间相互作用的Rx线圈结构域的不同表面。马铃薯（Solanum tuberosum）抗病蛋白Rx具有模块化结构，包含卷曲卷曲（CC）、核苷酸结合（NB）和富赖氨酸重复（LRR）结构域，介导对马铃薯x病毒的抗性。Rx n端CC结构域与Rx NB-LRR区域发生分子内相互作用，并与Rx辅助因子RanGAP2 （Ran gtpase -激活蛋白2）发生分子间相互作用。本文报道了RanGAP2中Rx CC结构域与Trp-Pro-Pro （WPP）结构域配合物的晶体结构。该结构表明Rx CC结构域与RanGAP2形成异源二聚体，与大麦抗病蛋白MLA10的CC结构域的同二聚体结构形成鲜明对比。基于结构的诱变鉴定了Rx CC结构域和RanGAP2 WPP结构域的残基，这些残基对它们在体外和体内的相互作用和功能至关重要。我们的研究结果揭示了Rx与RanGAP2相互作用的分子机制，并确定了Rx CC结构域参与分子内和分子间相互作用的不同表面。
Background: The interaction of the potato disease resistance protein Rx with RanGAP2 is important for virus resistance. Results: The crystal structure of the complex of the Rx and RanGAP2 N-terminal domains was determined. Conclusion: The two proteins bind primarily through hydrophobic interactions. Significance: This work reveals the distinct surfaces of the Rx coiled-coil domain involved in intra- and intermolecular interactions.The potato (Solanum tuberosum) disease resistance protein Rx has a modular arrangement that contains coiled-coil (CC), nucleotide-binding (NB), and leucine-rich repeat (LRR) domains and mediates resistance to potato virus X. The Rx N-terminal CC domain undergoes an intramolecular interaction with the Rx NB-LRR region and an intermolecular interaction with the Rx cofactor RanGAP2 (Ran GTPase-activating protein 2). Here, we report the crystal structure of the Rx CC domain in complex with the Trp-Pro-Pro (WPP) domain of RanGAP2. The structure reveals that the Rx CC domain forms a heterodimer with RanGAP2, in striking contrast to the homodimeric structure of the CC domain of the barley disease resistance protein MLA10. Structure-based mutagenesis identified residues from both the Rx CC domain and the RanGAP2 WPP domain that are crucial for their interaction and function in vitro and in vivo. Our results reveal the molecular mechanism underlying the interaction of Rx with RanGAP2 and identify the distinct surfaces of the Rx CC domain that are involved in intramolecular and intermolecular interactions.