Abstract：
Chemoselective modification of specific residues within a given protein poses a significant challenge, as the microenvironment of amino acid residues in proteins is variable. Developing a universal molecular platform with tunable chemical warheads can provide powerful tools for precisely labeling specific amino acids in proteins. Cysteine and lysine are hot targets for chemoselective modification, but current cysteine/lysine-selective warheads face challenges due to cross-reactivity and unstable reaction products. In this study, a versatile fluorescent platform is developed for highly selective modification of cysteine/lysine under biocompatible conditions. Chloro- or phenoxy-substituted NBSe derivatives effectively labeled cysteine residues in the cellular proteome with high specificity. This finding also led to the development of phenoxy-NBSe phototheragnostic for the diagnosis and activatable photodynamic therapy of GSH-overexpressed cancer cells. Conversely, alkoxy-NBSe derivatives are engineered to selectively react with lysine residues in the cellular environment, exhibiting excellent anti-interfering ability against thiols. Leveraging a proximity-driven approach, alkoxy-NBSe probes are successfully designed to demonstrate their utility in bioimaging of lysine deacetylase activity. This study also achieves integrating a small photosensitizer into lysine residues of proteins in a regioselective manner, achieving photoablation of cancer cells activated by overexpressed proteins.
摘要：
在给定的蛋白质内的特定残基的化学选择性修饰提出了重大的挑战。因为蛋白质中氨基酸残基的微环境是可变的。开发具有可调化学弹头的通用分子平台可以为精确标记蛋白质中的特定氨基酸提供强大的工具。半胱氨酸和赖氨酸是化学选择性修饰的热门靶标，但是由于交叉反应性和不稳定的反应产物，目前的半胱氨酸/赖氨酸选择性弹头面临挑战。在这项研究中,开发了一种通用的荧光平台，用于在生物相容性条件下对半胱氨酸/赖氨酸进行高选择性修饰。氯-或苯氧基-取代的NBSe衍生物以高特异性有效地标记细胞蛋白质组中的半胱氨酸残基。这一发现还导致了苯氧基-NBSe光热不可知的发展，用于GSH过表达的癌细胞的诊断和可激活的光动力疗法。相反，烷氧基-NBSe衍生物被设计为在细胞环境中选择性地与赖氨酸残基反应，对硫醇具有优异的抗干扰能力。利用接近驱动的方法，成功地设计了烷氧基-NBSe探针以证明其在赖氨酸脱乙酰酶活性的生物成像中的实用性。这项研究还实现了以区域选择性方式将小的光敏剂整合到蛋白质的赖氨酸残基中，实现由过度表达的蛋白质激活的癌细胞的光消融。
