Structure of the male determinant factor for Brassica self-incompatibility
Structure of the male determinant factor for Brassica self-incompatibility
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DOI：
10.1074/jbc.m305305200
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发表时间：
2003-09-19
影响因子：
4.8
通讯作者：
Shirakawa, M
中科院分区：
文献类型：
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作者：
Mishima, M;Takayama, S;Shirakawa, M
许多开花植物具有自交不亲和系统，以防止近亲繁殖。在甘蓝型油菜中，柱头受体与S位点富含半胱氨酸的蛋白11(又称S位点富含半胱氨酸蛋白)之间的相互作用是通过柱头受体与S位点之间的单倍型特异性相互作用而建立的。在这里，我们描述了S-8-单倍型(S-8-SP11)的SP11蛋白的溶液结构，它与同一单倍型的柱头因子特异结合。它折叠成一个类似植物防御素的阿尔法/贝塔夹心结构。对结构完整性重要的残基在等位基因SP11s中高度保守，表明存在共同的折叠模式。基于结构的序列比对和等位基因SP11的同源建模发现了一个高变量(HV)区域，该区域被认为形成了一个从蛋白质体内凸出的环，该环适合于溶剂暴露。我们认为HV区可以作为柱头受体的特异性结合部位。
Many flowering plants possess a self-incompatibility system to prevent inbreeding. In Brassica rapa, self/ non-self recognition in mating is established through S-haplotype-specific interactions between stigma receptors and S-locus protein 11 (SP11, also called S-locus cysteine-rich protein) that is encoded at the highly polymorphic S-locus. Here we describe the solution structure of the SP11 protein of the S-8-haplotype ( S-8-SP11), which specifically binds to the stigma factor of the same haplotype. It folds into an alpha/beta sandwich structure that resembles those of plant defensins. Residues important for structural integrity are highly conserved among the allelic SP11s, suggesting the existence of a common folding pattern. Structure-based sequence alignment and homology modeling of allelic SP11 identified a hypervariable (HV) region, which is thought to form a loop that bulges out from the body of the protein that is amenable to solvent exposure. We suggest that the HV region could serve as a specific binding site for the stigma receptor.