Lysine methylation in protein is one important epigenetic mechanism that regulates diverse biological processes but is challenging to study due to the large variability in methylation levels and sites. Here, we show that supramolecular hosts such as calixarenes and cucurbiturils can be applied in the background electrolyte (BGE) of capillary electrophoresis (CE) for highly effective separation of post-translationally methylated histone peptides. The molecular recognition event causes a shift in the electrophoretic mobility of the peptide, allowing affinity measurement for binding between the synthetic receptor and various methylated lysine species. Successful separation of the H3 peptides carrying different methylation levels at the K9 position can be achieved using CX4 and CX6 as the BGE additives in CE, enabling monitoring of the activity of the histone lysine demethylase JMJD2E. This reveals the power of combining high resolution CE with synthetic hosts for study of protein methylation, and the method should be capable of analyzing complex biological samples for better understanding of the functions of histone methylation.

中文翻译：

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通过宿主辅助毛细管电泳分离甲基化组蛋白肽

蛋白质中的赖氨酸甲基化是一种重要的表观遗传机制，可调节多种生物过程，但由于甲基化水平和位点的巨大变异性，研究起来具有挑战性。在这里，我们展示了杯芳烃和葫芦脲等超分子主体可应用于毛细管电泳 (CE) 的背景电解质 (BGE) 中，以高效分离翻译后甲基化组蛋白肽。分子识别事件导致肽的电泳迁移率发生变化，从而允许对合成受体和各种甲基化赖氨酸物质之间的结合进行亲和力测量。使用CX4和CX6可以成功分离在 K9 位置携带不同甲基化水平的 H3 肽作为 CE 中的 BGE 添加剂，能够监测组蛋白赖氨酸脱甲基酶 JMJD2E 的活性。这揭示了将高分辨率 CE 与合成宿主相结合来研究蛋白质甲基化的能力，并且该方法应该能够分析复杂的生物样品，以便更好地了解组蛋白甲基化的功能。