Deng Dandan, Yang Xu, An Jinying, Zhang Kai, Lin Shen, Dong XiangChao
Research Center for Analytical Sciences, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China.
2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Department of Biochemistry and Molecular Biology, Tianjin Medical University, Tianjin, 300070, China; Tianjin Key Laboratory of Retinal Functions and Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Tianjin, 300384, China.
Talanta. 2021 Mar 1;224:121819. doi: 10.1016/j.talanta.2020.121819. Epub 2020 Oct 29.
Lysine methylations are common protein post-translational modifications (PTMs), that play significant roles in regulating gene activities. Studies of their functions and connections with diseases have important values. However, due to the small variations from their native structures and very low component proportions, it is very difficult to extract methylated peptides from biological mixtures. In this research, a new material that utilizes sulfonated calix[4]arene (SC4A) as the recognition unit and silica coated with TiO as carrier, denoted as SiO@TiO@SC4A, was synthesized. The equilibrium binding experiments demonstrated that SiO@TiO@SC4A can identify lysine and arginine methylation and peptides with these methylated residues. The maximum isotherm binding capacities are 70.0, 55.9, 31.4 and 24.8 μmol g for Lys(Me), Lys(Me), Lys(Me) and Lys, respectively. It demonstrated that the higher the degree of methylation, the stronger the interactions. In addition, the analyses of high performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) demonstrated that peptides with methylated lysine or arginine can be selectively extracted from spiked histone trypsin digestion. The recoveries for the spiked GGAK(Me)R, GGAKR(Me) and GGAK(Me)R are 83%, 78%, and 84% respectively. The experiments from the nuclear extracts of HeLa cells also illustrated that SiO@TiO@SC4A holds a potential in the enrichment and identification of lysine methylations.
赖氨酸甲基化是常见的蛋白质翻译后修饰（PTM），在调节基因活性中发挥着重要作用。对其功能以及与疾病关联的研究具有重要价值。然而，由于它们与天然结构的差异微小且组分比例极低，从生物混合物中提取甲基化肽非常困难。在本研究中，合成了一种以磺化杯[4]芳烃（SC4A）作为识别单元、以包覆TiO的二氧化硅为载体的新材料，记为SiO@TiO@SC4A。平衡结合实验表明，SiO@TiO@SC4A能够识别赖氨酸和精氨酸甲基化以及带有这些甲基化残基的肽。对于单甲基赖氨酸（Lys(Me)）、二甲基赖氨酸（Lys(Me)）、三甲基赖氨酸（Lys(Me)）和赖氨酸（Lys），最大等温线结合容量分别为70.0、55.9、31.4和24.8 μmol g。结果表明甲基化程度越高，相互作用越强。此外，高效液相色谱（HPLC）和基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF）分析表明，带有甲基化赖氨酸或精氨酸的肽可以从加标的组蛋白胰蛋白酶消化产物中被选择性提取。加标的GGAK(Me)R、GGAKR(Me)和GGAK(Me)R的回收率分别为83%、78%和84%。来自HeLa细胞核提取物的实验也表明，SiO@TiO@SC4A在赖氨酸甲基化的富集和鉴定方面具有潜力。
