首页>
外文期刊>The biochemical journal
>Conserved extracellular cysteine residues and cytoplasmic loop–loop interplay are required for functionality of the heptahelical MLO protein
【24h】
Conserved extracellular cysteine residues and cytoplasmic loop–loop interplay are required for functionality of the heptahelical MLO protein
pWe performed a structure–function analysis of the plasma membrane-localized plant-specific barley (iHordeum vulgare/i) MLO (powdery-mildew-resistance gene o) protein. Invariant cysteine and proline residues, located either in extracellular loops or transmembrane domains that have been conserved in MLO proteins for more than 400 million years, were found to be essential for MLO functionality and/or stability. Similarly to many metazoan G-protein-coupled receptors known to function as homo- and hetero-oligomers, FRET (fluorescence resonance energy transfer) analysis revealed evidence for iin planta/i MLO dimerization/oligomerization. Domain-swap experiments with closely related wheat and rice as well as diverged iArabidopsis/i MLO isoforms demonstrated that the identity of the C-terminal cytoplasmic tail contributes to MLO activity. Likewise, analysis of a progressive deletion series revealed that integrity of the C-terminus determines both MLO accumulation and functionality. A series of domain swaps of cytoplasmic loops with the wheat (iTriticum aestivum/i) orthologue, iTa/iMLO-B1, provided strong evidence for co-operative loop–loop interplay either within the protein or between MLO molecules. Our data indicate extensive intramolecular co-evolution of cytoplasmic domains in the evolutionary history of the MLO protein family./p
展开▼
机译:>我们对定位在质膜上的植物特异性大麦(Hordeum vulgare i>)MLO(抗粉煤灰基因o)蛋白进行了结构-功能分析。发现位于MLO蛋白中已保存超过400亿年的细胞外环或跨膜结构域中的不变半胱氨酸和脯氨酸残基对于MLO功能和/或稳定性至关重要。与许多已知具有同型和异型寡聚体的后生动物G蛋白偶联受体相似,FRET(荧光共振能量转移)分析揭示了植物中MLO二聚/低聚的证据。用紧密相关的小麦和水稻以及不同的拟南芥MLO亚型进行的域交换实验表明,C末端胞质尾巴的身份有助于MLO活性。同样,对进行性缺失序列的分析表明,C末端的完整性决定了MLO的积累和功能。与小麦直系同源物 Ta i> MLO-B1进行的一系列胞质环结构域交换,为在小麦中的合作性环-环相互作用提供了有力的证据。蛋白质或MLO分子之间。我们的数据表明,在MLO蛋白家族的进化史中,胞质域发生了广泛的分子内共同进化。 p>
展开▼