Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Starkville MS, 39762.
Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Starkville MS, 39762; Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, Nanjing 210014, China.
Mol Cell Proteomics. 2019 Dec;18(12):2359-2372. doi: 10.1074/mcp.RA119.001426. Epub 2019 Sep 6.
Lysine succinylation has been recognized as a post-translational modification (PTM) in recent years. It is plausible that succinylation may have a vaster functional impact than acetylation because of bulkier structural changes and more significant charge differences on the modified lysine residue. Currently, however, the quantity and identity of succinylated proteins and their corresponding functions in cereal plants remain largely unknown. In this study, we estimated the native succinylation occupancy on lysine was between 2% to 10% in developing rice seeds. Eight hundred fifty-four lysine succinylation sites on 347 proteins have been identified by a thorough investigation in developing rice seeds. Six motifs were revealed as preferred amino acid sequence arrangements for succinylation sites, and a noteworthy motif preference was identified in proteins associated with different biological processes, molecular functions, pathways, and domains. Remarkably, heavy succinylation was detected on major seed storage proteins, in conjunction with critical enzymes involved in central carbon metabolism and starch biosynthetic pathways for rice seed development. Meanwhile, our results showed that the modification pattern of nonenzymatically succinylated proteins was different from those of the proteins isolated from cells in Western blots, suggesting that succinylation is not generated via nonenzymatic reaction in the cells, at least not completely. Using the acylation data obtained from the same rice tissue, we mapped many sites harboring lysine succinylation, acetylation, malonylation, crotonylation, and 2-hydroxisobutyrylation in rice seed proteins. A striking number of proteins with multiple modifications were shown to be involved in critical metabolic events. Given that these modification moieties are intermediate products of multiple cellular metabolic pathways, these targeted lysine residues may mediate the crosstalk between different metabolic pathways via modifications by different moieties. Our study exhibits a platform for extensive investigation of molecular networks administrating cereal seed development and metabolism via PTMs.
赖氨酸琥珀酰化近年来被认为是一种翻译后修饰（PTM）。由于琥珀酰化赖氨酸残基上的结构变化更大，电荷差异更显著，因此它可能具有比乙酰化更广泛的功能影响。然而，目前谷物植物中琥珀酰化蛋白的数量和身份及其相应的功能在很大程度上仍然未知。在这项研究中，我们估计发育中的水稻种子中赖氨酸的天然琥珀酰化占有率在 2%到 10%之间。通过对发育中的水稻种子进行深入研究，我们鉴定了 347 种蛋白质上的 854 个赖氨酸琥珀酰化位点。揭示了六个基序作为琥珀酰化位点的首选氨基酸序列排列，并且在与不同生物学过程、分子功能、途径和结构域相关的蛋白质中发现了一个值得注意的基序偏好。值得注意的是，在与中央碳代谢和淀粉生物合成途径相关的关键酶一起，在主要的种子贮藏蛋白上检测到了强烈的琥珀酰化。同时，我们的结果表明，非酶促琥珀酰化蛋白的修饰模式与从 Western blot 中分离的细胞蛋白不同，这表明琥珀酰化不是在细胞中通过非酶促反应产生的，至少不完全是。使用从同一水稻组织获得的酰化数据，我们在水稻种子蛋白中绘制了许多含有赖氨酸琥珀酰化、乙酰化、丙二酰化、巴豆酰化和 2-羟异丁酰化的位点。许多具有多种修饰的蛋白质被证明参与了关键的代谢事件。鉴于这些修饰基团是多个细胞代谢途径的中间产物，这些靶向赖氨酸残基可能通过不同的基团修饰来介导不同代谢途径之间的串扰。我们的研究展示了一个平台，通过 PTM 广泛研究管理谷物种子发育和代谢的分子网络。
