通过其受体GID1识别吉伯雷林的结构基础
Asako Shimada1, Miyako Ueguchi-Tanaka, Toru Nakatsu
1Bioscience and Biotechnology Center, Nagoya University, Nagoya, Aichi 464-8601, Japan.
Nature
|November 28, 2008
概括
对于植物生长至关重要的Gibberellin不敏感矮人1 (GID1) 受体,是从激素敏感的脂质酶进化而来的. 结构分析揭示了基贝瑞林结合的关键残留物和进化适应物,以增强亲和力和选择性.
科学领域:
- 植物生物学 植物生物学
- 分子生物学分子生物学
- 生物化学 生物化学
背景情况:
- 吉伯雷林 (GAs) 是重要的植物激素,调节发育.
- 核GA受体GIBBERELLIN INSENSITIVE DWARF1 (GID1) 与激素敏感脂酶 (HSL) 具有结构上的相似性.
研究的目的:
- 为了阐明Oryza sativa GID1 (OsGID1) 与GA(4) 和GA(3) 复合的晶体结构.
- 研究特定氨基酸残留在GA结合和通过突变发生的亲缘关系中的作用.
- 了解GID1受体的进化起源和适应.
主要方法:
- 通过X射线晶体学,确定与GA(4) 和GA(3) 结合的OsGID1的1.9 Å分辨率结构.
- 从晶体结构中识别出的关键残留物的位点定向突变发生.
- 用GA结合测定来评估突变对结合亲和力的影响.
主要成果:
- OsGID1的结构揭示了一种α/β-酶折叠,类似于HSL,但具有氨基终端盖,以及与HSL基质结合部位相对应的GA结合口袋.
- 突变发生证实了已识别的残留物对GA结合的重要性,因为突变导致活性显著减少或消除.
- 特定突变 (Ile133到Leu或Val) 增加了对基化GA的结合亲和力,表明进化微调.
结论:
- GID1受体从HSL进化,获得氨基终端盖并适应其GA结合口袋.
- 在GID1的氨基酸残留物中的进化修饰增强了对生物活性气体的亲和力和选择性.
- 结构和功能分析提供了关于植物GA感知和信号传递的分子机制的见解.
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