Directed Evolution of Fluorescent Proteins in Bacteria.

Sara Mattson, Geraldine N Tran, Erik A Rodriguez

Methods in molecular biology (Clifton, N.J.) 2023

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Directed evolution has revolutionized the way scientists create new biomolecules not found in nature. Error-prone polymerase chain reaction (PCR) introduces random mutations and was used to evolve jellyfish and coral fluorescent proteins in bacteria. We describe a novel method for the directed evolution of a far-red fluorescent protein in E. coli. The new method used genes to produce fluorophores inside E. coli and allowed changing the native fluorophore, phycocyanobilin, for a second small-molecule fluorophore, biliverdin. The directed evolution blueshifted the fluorescence, which enhanced the quantum yield to produce a brighter fluorescent protein. Finally, the evolution selected fluorescent proteins that expressed in large quantities in E. coli. The evolved fluorescent protein was named the small ultra-red fluorescent protein (smURFP) and was biophysically as bright as the enhanced green fluorescent protein (EGFP). This chapter describes the materials and methods used to evolve a far-red fluorescent protein in bacteria. While the focus is a fluorescent protein, the protocol is adaptable for the evolution of other biomolecules in bacteria when using a proper selection strategy. © 2023. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.

Citation

Sara Mattson, Geraldine N Tran, Erik A Rodriguez. Directed Evolution of Fluorescent Proteins in Bacteria. Methods in molecular biology (Clifton, N.J.). 2023;2564:75-97