EcoFlex: A Multifunctional MoClo Kit for E. coli Synthetic Biology

• Published in: ACS synthetic biology Vol. 5; no. 10; pp. 1059 - 1069
• Main Authors: Moore, Simon J, Lai, Hung-En, Kelwick, Richard J. R, Chee, Soo Mei, Bell, David J, Polizzi, Karen Marie, Freemont, Paul S
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 21-10-2016
• Subjects: Escherichia coli - genetics; Escherichia coli - metabolism; Gene Library; Genetic Engineering - methods; Genetic Vectors; Indoles - metabolism; Promoter Regions, Genetic; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Reproducibility of Results; Synthetic Biology - methods; synthetic biology; violacein; Golden Gate; cell-free protein synthesis; Escherichia coli; recombinant protein production
• DOI: 10.1021/acssynbio.6b00031
• EISSN: 2161-5063

Golden Gate cloning is a prominent DNA assembly tool in synthetic biology for the assembly of plasmid constructs often used in combinatorial pathway optimization, with a number of assembly kits developed specifically for yeast and plant-based expression. However, its use for synthetic biology in commonly used bacterial systems such as Escherichia coli has surprisingly been overlooked. Here, we introduce EcoFlex a simplified modular package of DNA parts for a variety of applications in E. coli, cell-free protein synthesis, protein purification and hierarchical assembly of transcription units based on the MoClo assembly standard. The kit features a library of constitutive promoters, T7 expression, RBS strength variants, synthetic terminators, protein purification tags and fluorescence proteins. We validate EcoFlex by assembling a 68-part containing (20 genes) plasmid (31 kb), characterize in vivo and in vitro library parts, and perform combinatorial pathway assembly, using pooled libraries of either fluorescent proteins or the biosynthetic genes for the antimicrobial pigment violacein as a proof-of-concept. To minimize pathway screening, we also introduce a secondary module design site to simplify MoClo pathway optimization. In summary, EcoFlex provides a standardized and multifunctional kit for a variety of applications in E. coli synthetic biology.