Complex structures of the abscisic acid receptor PYL3/RCAR13 reveal a unique regulatory mechanism.
Complex structures of the abscisic acid receptor PYL3/RCAR13 reveal a unique regulatory mechanism.
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DOI：
10.1016/j.str.2012.02.019
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发表时间：
2012-05
期刊：
影响因子：
5.7
通讯作者：
Xingliang Zhang;Qi Zhang;Qi Xin;Lin Yu;Z. Wang;Wei Wu;Lun Jiang;Guoqiang Wang;Wenli Tian-Wenli-Tia
中科院分区：
文献类型：
--
作者：
Xingliang Zhang;Qi Zhang;Qi Xin;Lin Yu;Z. Wang;Wei Wu;Lun Jiang;Guoqiang Wang;Wenli Tian-Wenli-Tia
脱落酸 (ABA) 控制许多生理过程并介导对非生物胁迫的适应性反应。报道了脱落酸受体 PYR/PYL/RCAR (PYL) 的 ABA 信号传导机制。然而，目前尚不清楚这些分子机制是否适用于其他 PYL。在此，报道了 PYL3 与 (+)-ABA、pyrabactin 和 HAB1 的复杂结构。在晶体中观察到的意想不到的反式同二聚体中间体在溶液中得到证实。 ABA结合的PYL3极大地促进了单体PYL3的生成，这可以过度增加抑制PP2Cs的效率。结构引导的生化实验表明 Ser195 是关键的中间体。有趣的是，吡拉巴汀以一种独特的非生产性模式与门关闭结合到 PYL3，这为脱落酸受体激动剂和拮抗剂的设计提供了线索。根据配体结合的PYLs构象的不同，PYLs家族可分为三个亚类，其中以PYL3为代表的反式二聚体亚类揭示了独特的调控机制。
Abscisic acid (ABA) controls many physiological processes and mediates adaptive responses to abiotic stresses. The ABA signaling mechanisms for abscisic acid receptors PYR/PYL/RCAR (PYLs) were reported. However, it remains unclear whether the molecular mechanisms are suitable for other PYLs. Here, complex structures of PYL3 with (+)-ABA, pyrabactin and HAB1 are reported. An unexpectedtrans-homodimer intermediate observed in the crystal is confirmed in solution. ABA-bound PYL3 greatly promotes the generation of monomeric PYL3, which can excessively increase the efficiency of inhibiting PP2Cs. Structure-guided biochemical experiments show that Ser195 accounts for the key intermediate. Interestingly, pyrabactin binds to PYL3 in a distinct nonproductive mode with gate closure, which sheds light on the design of agonists and antagonists for abscisic acid receptors. According to different conformations of ligand-bound PYLs, the PYLs family can be divided into three subclasses, among which thetrans-dimeric subclass, represented by PYL3, reveals a distinct regulatory mechanism.