Nature子刊：清华大学陈国强团队开发新型正交转录突变系统，蛋白质进化速度提升150万倍

Core Viewpoint - The article discusses the development of an orthogonal transcription mutation system (OTM) that significantly enhances the efficiency and specificity of protein evolution, addressing limitations in traditional methods and expanding applications in both model and non-model organisms [2][6]. Group 1: System Development - The OTM system integrates three broadly compatible phage RNA polymerases with two deaminase variants, creating a modular platform for protein evolution [3]. - The core design allows RNA polymerase to unwind DNA, enabling deaminases to edit exposed single-stranded DNA, achieving base mutations of C:G to T:A and A:T to G:C types [3][4]. - The system can complete directed evolution of proteins in just one day, with mutation efficiency improved by 1.5 million times compared to spontaneous mutations [3][6]. Group 2: Functional Capabilities - The research team successfully constructed dual-function orthogonal transcription mutation elements that can introduce both C:G to T:A and A:T to G:C mutations simultaneously [4]. - The system demonstrates orthogonality, allowing different phage RNA polymerases to specifically recognize their respective promoters, minimizing cross-interference [5]. - The OTM system shows excellent performance in both non-model organisms (e.g., Halomonas bluephagenesis) and model organisms (e.g., E. coli), overcoming previous efficiency challenges in non-model industrial strains [5][6]. Group 3: Practical Applications - The system has been applied to mutate fluorescent proteins and pigment proteins, resulting in engineered strains with various colors [5]. - Targeted mutations in cytoskeletal and division-related proteins led to engineered strains with diverse morphologies, providing new insights for morphological engineering [5]. - In industrial applications, the system successfully evolved σ70 global transcription regulator RpoD and lysine export protein LysE, enhancing L-arginine tolerance and transport capabilities [5][6]. Group 4: Future Prospects - The OTM system has significant potential for further development, including integrating other types of deaminases to diversify mutation libraries [6]. - Future exploration may focus on the system's compatibility and applicability in other non-model organisms [6]. - The mutation system can accelerate the optimization of key enzymes in biomanufacturing, contributing to the advancement of a green bio-economy [6].