Arabinogalactan proteins (AGPs) encompass a diverse group of plant cell wall proteoglycans, which play an essential role in plant development, signaling, plant‐microbe interactions, and many others. Although they are widely distributed throughout the plant kingdom and extensively studied, they remain largely unexplored in the lower plants, especially in seaweeds. Ulva species have high economic potential since various applications were previously described including bioremediation, biofuel production, and as a source of bioactive compounds. This article presents the first experimental confirmation of AGP‐like glycoproteins in Ulva species and provides a simple extraction protocol of Ulva lactuca AGP‐like glycoproteins, their partial characterization and unique comparison to scarcely described Solanum lycopersicum AGPs. The reactivity with primary anti‐AGP antibodies as well as Yariv reagent showed a great variety between Ulva lactuca and Solanum lycopersicum AGP‐like glycoproteins. While the amino acid analysis of the AGP‐like glycoproteins purified by the β‐d‐glucosyl Yariv reagent showed a similarity between algal and land plant AGP‐like glycoproteins, neutral saccharide analysis revealed unique glycosylation of the Ulva lactuca AGP‐like glycoproteins. Surprisingly, arabinose and galactose were not the most prevalent monosaccharides and the most outstanding was the presence of 3‐O‐methyl‐hexose, which has never been described in the AGPs. The exceptional structure of the Ulva lactuca AGP‐like glycoproteins implies a specialized adaptation to the marine environment and might bring new insight into the evolution of the plant cell wall.

中文翻译：

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与陆地植物AGP相比，来自Ulva lactuca（Chlorophyta）的类阿拉伯半乳聚糖糖蛋白显示出独特的功能

阿拉伯半乳聚糖蛋白（AGP）涵盖了各种各样的植物细胞壁蛋白聚糖，它们在植物发育，信号传导，植物与微生物的相互作用以及许多其他过程中起着至关重要的作用。尽管它们广泛分布于整个植物界并进行了广泛研究，但它们在较低的植物中，尤其是在海藻中仍未开发。由于先前描述了各种应用，包括生物修复，生物燃料生产以及作为生物活性化合物的来源，因此Ulva物种具有很高的经济潜力。本文介绍了Ulva物种中AGP样糖蛋白的第一个实验确认，并提供了Ulva lactuca的简单提取方案类似于AGP的糖蛋白，其部分特征以及与鲜为人知的茄果AGP的独特比较。与抗AGP一级抗体和Yariv试剂的反应性表明，Ulva lactuca和茄茄AGP样糖蛋白之间存在很大差异。尽管通过β- d-葡萄糖基Yariv试剂纯化的AGP样糖蛋白的氨基酸分析显示藻类和陆地植物AGP样糖蛋白之间存在相似性，但中性糖分析显示了Ulva lactuca AGP样糖蛋白具有独特的糖基化作用。令人惊讶的是，阿拉伯糖和半乳糖不是最普遍的单糖，最突出的是3 O的存在。-甲基己糖，在AGP中从未描述过。Ulva lactuca AGP样糖蛋白的特殊结构意味着对海洋环境的专门适应，并可能为植物细胞壁的进化带来新的见识。