1. Directed evolution of the B. subtilis nitroreductase YfkO improves activation of the PET-capable probe SN33623 and CB1954 prodrug.
- Author
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Rich, Michelle H., Sharrock, Abigail V., Ashoorzadeh, Amir, Patterson, Adam V., Smaill, Jeff B., and Ackerley, David F.
- Subjects
DNA damage ,CANCER genes ,GENE therapy ,CANCER treatment - Abstract
Objectives: To use directed evolution to improve YfkO-mediated reduction of the 5-nitroimidazole PET-capable probe SN33623 without impairing conversion of the anti-cancer prodrug CB1954. Results: Two iterations of error-prone PCR, purifying selection, and FACS sorting in a DNA damage quantifying GFP reporter strain were used to identify three YfkO variants able to sensitize E. coli host cells to at least 2.4-fold lower concentrations of SN33623 than the native enzyme. Two of these variants were able to be purified in a functional form, and in vitro assays revealed these were twofold and fourfold improved in k
cat /KM with SN33623 over wild type YfkO. Serendipitously, the more-active variant was also nearly fourfold improved in kcat /KM versus wild type YfkO in converting CB1954 to a genotoxic drug. Conclusions: The enhanced activation of the PET imaging probe SN33623 and CB1954 prodrug exhibited by the lead evolved variant of YfkO offers prospects for improved enzyme-prodrug therapy. [ABSTRACT FROM AUTHOR]- Published
- 2021
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