Department of Chemistry, Boston College, Merkert Chemistry Center, 2609 Beacon Street, Chestnut Hill, MA, 02467, USA.
Angew Chem Int Ed Engl. 2020 Aug 17;59(34):14246-14250. doi: 10.1002/anie.202000837. Epub 2020 Jul 2.
We report a novel conjugation of N-terminal cysteines (NCys) that proceeds with fast kinetics and exquisite selectivity, thereby enabling facile modification of NCys-bearing proteins in complex biological milieu. This new NCys conjugation proceeds via a thiazolidine boronate (TzB) intermediate that results from fast (k : ≈5000 m s ) and reversible conjugation of NCys with 2-formylphenylboronic acid (FPBA). We designed a FPBA derivative that upon TzB formation elicits intramolecular acyl transfer to give N-acyl thiazolidines. In contrast to the quick hydrolysis of TzB, the N-acylated thiazolidines exhibit robust stability under physiologic conditions. The utility of the TzB-mediated NCys conjugation is demonstrated by rapid and non-disruptive labeling of two enzymes. Furthermore, applying this chemistry to bacteriophage allows facile chemical modification of phage libraries, which greatly expands the chemical space amenable to phage display.
我们报告了一种新型的 N 端半胱氨酸（NCys）缀合反应，该反应具有快速动力学和极高的选择性，从而能够在复杂的生物环境中轻松修饰含有 NCys 的蛋白质。这种新的 NCys 缀合反应通过噻唑烷硼酸酯（TzB）中间体进行，该中间体是由 NCys 与 2-醛基苯硼酸（FPBA）快速（k：≈5000 m s）和可逆反应形成的。我们设计了一种 FPBA 衍生物，在形成 TzB 后会引发分子内酰基转移，生成 N-酰基噻唑烷。与 TzB 的快速水解形成鲜明对比的是，N-酰化的噻唑烷在生理条件下表现出很强的稳定性。TzB 介导的 NCys 缀合的实用性通过两种酶的快速和非破坏性标记得到了证明。此外，将该化学方法应用于噬菌体允许噬菌体文库的简便化学修饰，这大大扩展了适用于噬菌体展示的化学空间。
