Cytokinin-induced structural adaptability of a Lupinus luteus PR-10 protein
Cytokinin-induced structural adaptability of a Lupinus luteus PR-10 protein
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DOI：
10.1111/j.1742-4658.2009.06892.x
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发表时间：
2009-03-01
期刊：
影响因子：
5.4
通讯作者：
Jaskolski, Mariusz
中科院分区：
文献类型：
--
作者：
Fernandes, Humberto;Bujacz, Anna;Jaskolski, Mariusz
植物发病相关蛋白（PR）第10类是17个PR蛋白家族中唯一存在于细胞内和细胞质内的一类。序列保守性和PR-10蛋白在植物界的广泛分布表明其在植物中具有不可缺少的功能，但其真正的生物学作用尚不清楚。几个同源物的晶体和溶液结构显示出相似的整体折叠和巨大的内腔，以及与类固醇急性调节蛋白相关的脂质转移结构域和细胞分裂素特异性结合蛋白的结构相似性，强烈表明PR-10蛋白具有配体结合作用。本文描述了经典PR-10蛋白[Lupinus luteus (yellow lupine) PR-10蛋白亚类2 LlPR-10.2B]与合成细胞分裂素N， N′-二苯脲之间的复合物结构。合成细胞分裂素在各种生物测定中显示出与天然细胞分裂素相似的活性。目前的1.95 A分辨率晶体学模型显示在蛋白质的疏水腔中有4个N， N'-二苯脲分子，并且随着配体的结合发生了一定程度的构象变化。LlPR-10.2B的结构适应性及其结合不同细胞分裂素的能力表明，该蛋白以及其他PR-10蛋白可能在植物细胞的水环境中充当细胞分裂素分子的储存库。
Plant pathogenesis-related (PR) proteins of class 10 are the only group among the 17 PR protein families that are intracellular and cytosolic. Sequence conservation and the wide distribution of PR-10 proteins throughout the plant kingdom are an indication of an indispensable function in plants, but their true biological role remains obscure. Crystal and solution structures for several homologues have shown a similar overall fold with a vast internal cavity which, together with structural similarities to the steroidogenic acute regulatory protein-related lipid transfer domain and cytokinin-specific binding proteins, strongly indicate a ligand-binding role for the PR-10 proteins. This article describes the structure of a complex between a classic PR-10 protein [Lupinus luteus (yellow lupine) PR-10 protein of subclass 2, LlPR-10.2B] and N, N'-diphenylurea, a synthetic cytokinin. Synthetic cytokinins have been shown in various bioassays to exhibit activity similar to that of natural cytokinins. The present 1.95 A resolution crystallographic model reveals four N, N'-diphenylurea molecules in the hydrophobic cavity of the protein and a degree of conformational changes accompanying ligand binding. The structural adaptability of LlPR-10.2B and its ability to bind different cytokinins suggest that this protein, and perhaps other PR-10 proteins as well, can act as a reservoir of cytokinin molecules in the aqueous environment of a plant cell.