Tea Research Institute, Qingdao Agricultural University, 700 Changcheng road, Qingdao, 266109, Shandong, China.
College of Life Science, Yantai University, Yantai, Shandong, China.
BMC Genomics. 2018 Nov 26;19(1):840. doi: 10.1186/s12864-018-5250-4.
N-Acetylation of lysine residues, a frequently occurring post-translational modification, plays important functions in regulating physiology and metabolism. However, the information of global overview of protein acetylome under nitrogen-starvation/resupply in tea (Camellia sinensis) leaves was limited. And the full function of lysine acetylated proteins of tea plants in nitrogen absorption and assimilation remains unclear.
Here, we performed the global review of lysine acetylome in tea leaves under nitrogen (N)-starvation/resupply, using peptide prefractionation, immunoaffinity enrichment, and coupling with high sensitive LC-MS/MS combined with affinity purification analysis. Altogether, 2229 lysine acetylation sites on 1286 proteins were identified, of which 16 conserved motifs in EKK, KK, KR, KHK, KN, KS, KT, KD, were extracted from 2180 acetylated peptides. Approximately, 36.76% of the acetylated lysines were located in the regions of ordered secondary structures. The most of the identified lysine acetylation proteins were located in the chloroplast (39%) and cytoplasm (29%). The largest group of acetylated proteins consisted of many enzymes, such as ATP synthase, ribosomal proteins and malate dehydrogenase [NADP], which were related to metabolism (38%) in the biological process. These acetylated proteins were mainly enriched in three primary protein complexes of photosynthesis: photosystem I, photosystem II and the cytochrome b6/f complex. And some acetylated proteins related to glycolysis and secondary metabolite biosynthesis were increased/decreased under N-resupply. Moreover, the PPI (protein-protein interaction) analysis revealed that the diverse interactions of identified acetylated proteins mainly involved in photosynthesis and ribosome.
The results suggested that lysine acetylated proteins might play regulating roles in metabolic process in tea leaves. The critical regulatory roles mainly involved in diverse aspects of metabolic processes, especially in photosynthesis, glycolysis and secondary metabolism. A lot of proteins related to the photosynthesis and glycolysis were found to be acetylated, including LHCA1, LHCA3, LHCB6, psaE, psaD, psaN, GAPDH, PEPC, ENL and petC. And some proteins related to flavonoids were also found to be acetylated, including PAL, DFR, naringenin 3-dioxygenase and CHI. The provided data may serve as important resources for exploring the physiological, biochemical, and genetic role of lysine acetylation in tea plants. Data are available via ProteomeXchange with identifier PXD008931.
赖氨酸残基的乙酰化修饰是一种常见的翻译后修饰，在调节生理和代谢过程中发挥着重要作用。然而，关于茶树叶片在氮饥饿/再供应下蛋白质乙酰组的整体概况的信息有限。并且，茶树中天冬氨酸酰化蛋白在氮吸收和同化中的全部功能仍不清楚。
在这里，我们使用肽预分级、免疫亲和富集和与高灵敏度 LC-MS/MS 结合的亲和纯化分析，对茶树叶片在氮饥饿/再供应下的赖氨酸乙酰组进行了全面的综述。总共鉴定了 1286 种蛋白质上的 2229 个赖氨酸乙酰化位点，其中 2180 个乙酰化肽中提取了 EKK、KK、KR、KHK、KN、KS、KT、KD 中的 16 个保守基序。大约 36.76%的乙酰化赖氨酸位于有序二级结构区域。鉴定的赖氨酸乙酰化蛋白大多数位于叶绿体（39%）和细胞质（29%）中。最大的乙酰化蛋白组由许多酶组成，如 ATP 合酶、核糖体蛋白和苹果酸脱氢酶[NADP]，这些酶与代谢（38%）有关。在生物过程中。这些乙酰化蛋白主要富集在光合作用的三个主要蛋白复合物中：光系统 I、光系统 II 和细胞色素 b6/f 复合物。并且，在氮再供应下，一些与糖酵解和次生代谢物生物合成相关的乙酰化蛋白增加/减少。此外，PPI（蛋白质-蛋白质相互作用）分析表明，鉴定的乙酰化蛋白的多种相互作用主要涉及光合作用和核糖体。
结果表明，赖氨酸酰化蛋白可能在茶树叶片的代谢过程中发挥调节作用。关键的调节作用主要涉及代谢过程的各个方面，特别是光合作用、糖酵解和次生代谢。发现许多与光合作用和糖酵解相关的蛋白质被乙酰化，包括 LHCA1、LHCA3、LHCB6、psaE、psaD、psaN、GAPDH、PEPC、ENL 和 petC。并且还发现一些与类黄酮相关的蛋白质被乙酰化，包括 PAL、DFR、柚皮素 3-双加氧酶和 CHI。提供的数据可作为探索赖氨酸乙酰化在茶树中的生理、生化和遗传作用的重要资源。数据可通过 ProteomeXchange 获得，标识符为 PXD008931。
