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Macrolide antibiotics are in high demand for clinical applications. Macrolides are biosynthesized via giant assembly line polyketide synthases (PKS) which are arranged in a modular fashion. Combinatorial biosynthetic methods have been used to produce diversified macrolides by reprograming these modules and modifying tailoring enzymes required for post synthetic modifications. However it is challenging due to the size and complexity of PKSs. To overcome this challenge, new enzymes for macrolide diversification could be obtained by directed evolution where a large number of enzyme variants need to be screened. Therefore it is important to develop high throughput screening methods to identify the enzyme variants. MphR is a promiscuous macrolide sensing transcriptional repressor protein which regulates a gene cassette where Green Fluorescence Protein (GFP) is expressed upon binding of the macrolide antibiotic ligand to MphR. A system of two plasmids contains the genes required for the sensing process. This research is basically an insight of improving the sensitivity of MphR biosensor using a gene knockout approach where a gene expressing a protein related to antibiotic resistance is knocked out from the E.coli chromosome to obtain higher sensitivity of the biosensor.

Publication Date



Macrolides, Biosensor, MphR, Transcriptional Repressor, Erythromycin


Biochemistry | Biochemistry, Biophysics, and Structural Biology | Chemicals and Drugs | Genetics and Genomics | Other Chemistry

Faculty Advisor/Mentor

Dr. Ashton Cropp

Is Part Of

VCU Graduate Research Posters

Transcriptional Repressor Protein based Macrolide Biosensor Development with Improved Sensitivity