Unidad de Fruticultura, Centro de Investigación y Tecnología Agroalimentaria, Zaragoza, Spain.
Front Plant Sci. 2012 Jun 27;3:139. doi: 10.3389/fpls.2012.00139. eCollection 2012.
Gametophytic self-incompatibility (GSI) is a mechanism in flowering plants, to prevent inbreeding and promote outcrossing. GSI is under the control of a specific locus, known as the S-locus, which contains at least two genes, the RNase and the SFB. Active S-RNases in the style are essential for rejection of haploid pollen, when the pollen S-allele matches one of two S-alleles of the diploid pistil. However, the nature of their mutual interactions at genetic and biochemical levels remain unclear. Thus, detailed understanding of the protein structure involved in GSI may help in discovering how the proteins involved in GSI may function and how they fulfill their biological roles. To this end, 3D models of the SC (S(f)) and two SI (S(8) and S(23)) S-RNases of almond were constructed, using comparative modeling tools. The modeled structures consisted of mixed α and β folds, with six helices and six β-strands. However, the self-compatible (S(f)) RNase contained an additional extended loop between the conserved domains RC4 and C5, which may be involved in the manifestation of self-compatibility in almond.
配子体自交不亲和性 (GSI) 是开花植物中的一种机制，用于防止近亲繁殖和促进异交。GSI 受特定基因座的控制，称为 S 基因座，该基因座至少包含两个基因，即 RNase 和 SFB。当花粉的 S 等位基因与二倍体雌蕊的两个 S 等位基因之一匹配时，花柱中的活性 S-RNases 对于拒绝单倍体花粉是必不可少的。然而，它们在遗传和生化水平上的相互作用的性质仍不清楚。因此，详细了解参与 GSI 的蛋白质结构可能有助于发现参与 GSI 的蛋白质如何发挥作用以及它们如何履行其生物学功能。为此，使用比较建模工具构建了杏仁的 SC（S(f)) 和两个 SI（S(8) 和 S(23)) S-RNases 的 3D 模型。建模结构由混合的 α 和 β 折叠组成，具有六个螺旋和六个 β 链。然而，自交亲和性 (S(f)) RNase 在保守结构域 RC4 和 C5 之间包含一个额外的扩展环，这可能参与了杏仁的自交亲和性表现。
