Structural basis for gibberellin recognition by its receptor GID1
Structural basis for gibberellin recognition by its receptor GID1
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DOI：
10.1038/nature07546
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发表时间：
2008-11-27
期刊：
影响因子：
64.8
通讯作者：
Matsuoka, Makoto
中科院分区：
文献类型：
--
作者：
Shimada, Asako;Ueguchi-Tanaka, Miyako;Matsuoka, Makoto
赤霉素（giberellins, GAs）是植物许多发育过程所必需的植物激素(1)。核GA受体GIBBERELLIN INSENSITIVEDWARF1 （GID1）具有与激素敏感脂肪酶（hsl）相似的初级结构（2,3）。在1.9埃分辨率下，我们分析了Oryza sativa GID1 （OsGID1）与GA(4)和GA(3)结合的晶体结构。这两种配合物的整体结构都显示出与hsl相似的α / β水解酶折叠，除了氨基末端盖。GA结合袋对应于hsl的底物结合位点。在OsGID1结构的基础上，我们诱变了GA结合的重要残基，并检测了它们的结合活性。它们几乎都表现出很少或没有活性，证实了结构分析显示的残基对GA结合很重要。用Leu或Val -残基取代il133，与松林卷木GID1s -的残基相对应，导致对GA（2 β -羟基化GA）的结合亲和力增加（34）(4)。这些结果表明，GID1起源于HSL，并在植物进化过程中通过修饰参与GA结合的氨基酸，使GID1对具有生物活性的GAs具有更高的亲和力和更严格的选择性。
Gibberellins ( GAs) are phytohormones essential for many developmental processes in plants(1). A nuclear GA receptor, GIBBERELLIN INSENSITIVEDWARF1 ( GID1), has a primary structure similar to that of the hormone- sensitive lipases (HSLs)(2,3). Here we analyse the crystal structure of Oryza sativa GID1 (OsGID1) bound with GA(4) and GA(3) at 1.9 angstrom resolution. The overall structure of both complexes shows an alpha/beta-hydrolase fold similar to that of HSLs except for an amino- terminal lid. The GA- binding pocket corresponds to the substrate- binding site of HSLs. On the basis of the OsGID1 structure, we mutagenized important residues for GA binding and examined their binding activities. Almost all of them showed very little or no activity, confirming that the residues revealed by structural analysis are important for GA binding. The replacement of Ile 133 with Leu or Val - residues corresponding to those of the lycophyte Selaginella moellendorffii GID1s - caused an increase in the binding affinity for GA(34), a 2 beta-hydroxylated GA(4). These observations indicate that GID1 originated from HSL and was further modified to have higher affinity and more strict selectivity for bioactive GAs by adapting the amino acids involved in GA binding in the course of plant evolution.