An orthogonal T7 replisome for continuous hypermutation and accelerated evolution in E. coli

• 成果类型: Article
• 署名作者: Diercks, Christian S.; Sondermann, Philipp; Rong, Cynthia; Gillis, Thomas G.; Ban, Yahui; Wang, Celine; Dik, David A.; Schultz, Peter G.
• 署名单位: Scripps Research Institute
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-10499
• DOI: 10.1126/science.adp9583
• 发表日期: 2025-08-07
• 页码: 618-622
• 关键词: rna-polymerase transcription; bacteriophage t7; replication system; dna-replication; directed evolution; in-vitro; lysozyme; complex; gene; mutagenesis

摘要

Systems that perform continuous hypermutation of designated genes without compromising the integrity of the host genome can substantially accelerate the evolution of new or enhanced protein functions. We describe an orthogonal DNA replication system in Escherichia coli based on the controlled expression of the replisome of bacteriophage T7 (T7-ORACLE). The system replicates circular plasmids that enable high transformation efficiencies and seamless integration into standard molecular biology workflows. Engineering of T7 DNA polymerase yielded variant proteins with mutation rates of 1.7 x 10-5 substitutions per base in vivo-100,000-fold above the genomic mutation rate. We demonstrated continuous evolution using the T7 replisome by expanding the substrate scope of TEM-1 beta-lactamase and increasing activity 5000-fold against clinically relevant monobactam and cephalosporin antibiotics in less than 1 week.