A bioconjugation strategy is reported that allows the derivatization of tyrosine side chains through triazolinedione-based “Y-clicking”. Blocked triazolinedione reagents were developed that, in contrast to classical triazolinedione reagents, can be purified before use, can be stored for a long time, and allow functionalization with a wider range of cargoes and labels. These reagents are bench-stable at room temperature but steadily release highly reactive triazolinediones upon heating to 40 °C in buffered media at physiological pH, showing a sharp temperature response over the 0 to 40 °C range. This conceptually interesting strategy, which is complementary to existing photo- or electrochemical bioorthogonal bond-forming methods, not only avoids the classical synthesis and handling difficulties of these highly reactive click-like reagents but also markedly improves the selectivity profile of the tyrosine conjugation reaction itself. It avoids oxidative damage and “off-target” tryptophan labeling, and it even improves site-selectivity in discriminating between different tyrosine side chains on the same protein or different polypeptide chains. In this research article, we describe the stepwise development of these reagents, from their short and modular synthesis to small-molecule model bioconjugation studies and proof-of-principle bioorthogonal chemistry on peptides and proteins.

中文翻译：

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热触发三唑啉二酮-酪氨酸生物共轭，具有改进的化学和位点选择性

据报道，一种生物共轭策略允许通过基于三唑啉二酮的“Y-点击”对酪氨酸侧链进行衍生化。与经典的三唑啉二酮试剂相比，开发了封闭的三唑啉二酮试剂，该试剂可以在使用前纯化，可以长期保存，并允许使用更广泛的货物和标签进行功能化。这些试剂在室温下是稳定的，但在生理 pH 值的缓冲介质中加热至 40 °C 时会稳定释放高反应性三唑啉二酮，在 0 至 40 °C 范围内表现出尖锐的温度响应。这种概念上有趣的策略是对现有光或电化学生物正交成键方法的补充，不仅避免了这些高反应性点击样试剂的经典合成和处理困难，而且还显着提高了酪氨酸缀合反应本身的选择性。 。它避免了氧化损伤和“脱靶”色氨酸标记，甚至提高了区分同一蛋白质或不同多肽链上不同酪氨酸侧链的位点选择性。在这篇研究文章中，我们描述了这些试剂的逐步发展，从它们的简短和模块化合成到小分子模型生物共轭研究以及肽和蛋白质的原理验证生物正交化学。