2021年7月2日，UCSF的Lei Wang团队在《美国化学会杂志》发表论文，宣布他们开发出一种基因编码的氟磺酰氧基苯甲酰赖氨酸，通过SuFEx化学进行蛋白质拓展共价键合。

研究人员在大肠杆菌和哺乳动物细胞中设计并编码了一种新的潜在生物活性Uaa，氟磺酰氧基苯甲酰赖氨酸(FSK)。由于FSK具有长而灵活的含氟硫酸芳基侧链，因此FSK在分子内和分子间、体外和活细胞中都特别擅长共价连接FSY无法连接的蛋白质位点。此外，该研究组创建了共价纳米体，不可逆地与细胞上的表皮生长因子受体(EGFR)结合，FSK和FSY针对EGFR的不同位置，以对抗潜在的突变抗性。

此外，研究小组建立了使用FSK和FSY，通过基因编码的化学交联来捕获活细胞中模糊的酶-底物的相互作用，使它们能够靶向Cys之外的残基，并在结合周围进行交联。FSK补充了FSY，扩大了目标的多样性和多功能性。它们共同提供了一个强大的、基因编码的、潜在的生物活性SuFEx系统，用于在体外和体内在多种蛋白质中创建共价键，这将在生物学研究和应用有广泛使用。

研究人员表示，在蛋白质中基因编码地引入新的化学键为生化研究、蛋白质工程和生物治疗应用提供了创新的途径。最近，潜在的生物活性非天然氨基酸(Uaas)被引入到蛋白质中，通过邻近反应共价靶向天然残基。芳基氟硫酸酯因其独特的生物相容性和通过硫(VI)氟交换(SuFEx)反应的多靶向性而特别吸引人。到目前为止，氟硫酸盐-l-酪氨酸(FSY)是唯一一个含有芳基氟硫酸盐的Uaa基因编码。FSY具有相对刚性和较短的侧链，限制了蛋白质靶向性的多样性和应用范围。

附：英文原文

Title: A Genetically Encoded Fluorosulfonyloxybenzoyl-l-lysine for Expansive Covalent Bonding of Proteins via SuFEx Chemistry

Author: Jun Liu, Li Cao, Paul C. Klauser, Rujin Cheng, Viktoriya Y. Berdan, Wei Sun, Nanxi Wang, Farid Ghelichkhani, Bingchen Yu, Sharon Rozovsky, Lei Wang

Issue&Volume: July 2, 2021

Abstract: Genetically introducing novel chemical bonds into proteins provides innovative avenues for biochemical research, protein engineering, and biotherapeutic applications. Recently, latent bioreactive unnatural amino acids (Uaas) have been incorporated into proteins to covalently target natural residues through proximity-enabled reactivity. Aryl fluorosulfate is particularly attractive due to its exceptional biocompatibility and multitargeting capability via sulfur(VI) fluoride exchange (SuFEx) reaction. Thus far, fluorosulfate-l-tyrosine (FSY) is the only aryl fluorosulfate-containing Uaa that has been genetically encoded. FSY has a relatively rigid and short side chain, which restricts the diversity of proteins targetable and the scope of applications. Here we designed and genetically encoded a new latent bioreactive Uaa, fluorosulfonyloxybenzoyl-l-lysine (FSK), in E. coli and mammalian cells. Due to its long and flexible aryl fluorosulfate-containing side chain, FSK was particularly useful in covalently linking protein sites that are unreachable with FSY, both intra- and intermolecularly, in vitro and in live cells. In addition, we created covalent nanobodies that irreversibly bound to epidermal growth factor receptors (EGFR) on cells, with FSK and FSY targeting distinct positions on EGFR to counter potential mutational resistance. Moreover, we established the use of FSK and FSY for genetically encoded chemical cross-linking to capture elusive enzyme–substrate interactions in live cells, allowing us to target residues aside from Cys and to cross-link at the binding periphery. FSK complements FSY to expand target diversity and versatility. Together, they provide a powerful, genetically encoded, latent bioreactive SuFEx system for creating covalent bonds in diverse proteins in vitro and in vivo, which will be widely useful for biological research and applications.

DOI: 10.1021/jacs.1c04259

Source: https://pubs.acs.org/doi/10.1021/jacs.1c04259