近日，瑞士苏黎世联邦理工学院Kathrin Lang及其研究团队揭示了劫持细菌ABC转运蛋白进行遗传密码扩展。这一研究成果发表在2025年10月15日出版的国际学术期刊《自然》上。

在这里，研究人员揭示了细胞ncAA摄取不良是有效遗传密码扩展的主要障碍，并通过劫持细菌ATP结合盒（ABC）转运体5来主动进口易于合成的异肽连接三肽，这些三肽在细胞内被加工成ncAA，从而克服了这一瓶颈。利用这种方法，该研究团队能够有效地编码各种以前无法获得的ncAAs，用生物正交和交联剂修饰蛋白质，翻译后修饰和化学酶偶联功能。然后，课题组人员设计了一个高通量定向进化平台来设计定制的运输系统，用于进口历史上难以有效吸收的ncAA。表达这些进化的转运体的基化大肠杆菌菌株以野生型效率促进单位点和多位点ncAA的结合。此外，研究人员调整了三肽支架用于两种不同的ncAAs的共运输，使它们能够有效地双重结合。总的来说，他们的研究表明，摄取系统的工程设计是一种强大的策略，可编程地导入化学多样化的构建模块。

据介绍，非规范氨基酸（ncAAs）的位点特异性编码为扩展蛋白质的功能库提供了强有力的工具。然而，其广泛的基础研究和生物技术应用主题受到当前ncAA合并策略的低效率的阻碍。

附：英文原文

Title: Hijacking a bacterial ABC transporter for genetic code expansion

Author: Iype, Tarun, Fottner, Maximilian, Bhm, Paul, Piedrafita, Carlos, Mller, Yannis, Groll, Michael, Lang, Kathrin

Issue&Volume: 2025-10-15

Abstract: The site-specific encoding of non-canonical amino acids (ncAAs) provides a powerful tool for expanding the functional repertoire of proteins1,2,3,4. Its widespread use for basic research and biotechnological applications is, however, hampered by the low efficiencies of current ncAA incorporation strategies. Here we reveal poor cellular ncAA uptake as a main obstacle to efficient genetic code expansion and overcome this bottleneck by hijacking a bacterial ATP-binding cassette (ABC) transporter5 to actively import easily synthesizable isopeptide-linked tripeptides that are processed into ncAAs within the cell. Using this approach, we enable efficient encoding of a variety of previously inaccessible ncAAs, decorating proteins with bioorthogonal6 and crosslinker7 moieties, post-translational modifications8,9 and functionalities for chemoenzymatic conjugation. We then devise a high-throughput directed evolution platform to engineer tailored transporter systems for the import of ncAAs that were historically refractory to efficient uptake. Customized Escherichia coli strains expressing these evolved transporters facilitate single and multi-site ncAA incorporation with wild-type efficiencies. Additionally, we adapt the tripeptide scaffolds for the co-transport of two different ncAAs, enabling their efficient dual incorporation. Collectively, our study demonstrates that engineering of uptake systems is a powerful strategy for programmable import of chemically diverse building blocks.

DOI: 10.1038/s41586-025-09576-w

Source: https://www.nature.com/articles/s41586-025-09576-w