对OXGR1的配体识别和信号传递的分子洞察力
Aijun Liu1,2, Yezhou Liu3, Yuanzhengyang Long3
1The Affiliated Dongguan Songshan Lake Central Hospital, Guangdong Medical University, Dongguan, Guangdong, China. liuaijun@cuhk.edu.cn.
G蛋白结合受体 (GPCR) GPR99/OXGR1通过单独的结合部位结合了两个不同的配体,即2-oxoglutarate和cysteinyl leukotriene E4 (LTE4). 低温电磁结构显示出独特的结合口袋,使双联体识别和差异信号通路成为可能.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 药理学 药理学是指药理学的学科.
背景情况:
- GPR99/OXGR1,也称为CysLT3受体,是一种G蛋白合受体 (GPCR),由不同的内源配体激活:2-oxoglutarate和cysteinyl leukotriene E4 (LTE4).
- 了解GPR99/OXGR1适应这些结构不相似的配体的分子机制,对于阐明其生物功能至关重要.
研究的目的:
- 确定GPR99/OXGR1对2-氧格酸盐和LTE的认可的结构基础4.
- 阐明每个连接体所使用的独特的结合点和激活机制.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来获得与2-oxoglutarate或LTE4.4结合的GPR99/OXGR1-Gq复合物的高分辨率结构.
- 用于研究关键残留物在配体结合和受体激活中的功能性作用,采用了位点导向的突变发生 (alanine替代).
主要成果:
- GPR99/OXGR1与2-oxoglutarate结合的结构揭示了跨膜领域内的双位点结合口袋,容纳了两个分子来完全激活受体.
- 使用LTE4的冷-EM结构确定了一个独特的结合部位,位于跨膜域3/4/5之间,位于细胞内循环2上方,这对2-氧格酸盐来说太小了.
- 突变性研究证实了这些位点的不同作用,突变影响2-oxoglutarate结合,对LTE4信号产生最小影响,反之亦然.
结论:
- GPR99/OXGR1利用结构上独特的结合口袋与2-oxoglutarate和LTE4相互作用,解释其结合这些多样化的配体的能力.
- 干特异激活导致差异信号传递,两种干主要激活Gq通路,而LTE4也激活Gi通路.
- 这些发现为GPR99/OXGR1.1的双联体识别和信号机制提供了关键的结构洞察力.
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