Thomas Anderson, Utah State University
Biology
Pradimicin, a small molecule produced by the soil bacterium Actinomadura hibisica, is a promising candidate as a combined antifungal/antiviral therapeutic. It is active against a broad-spectrum of opportunistic, pathogenic fungi, interferes with the replication of influenza virus, and inhibits the reproduction of HIV-1. Toxicity and solubility problems have hindered past efforts to develop pradimicin as a therapeutic. Our research focuses on elucidating the bio-synthetic pathway of pradimicin in order to design and chemoenzymatically create pradimicin structural analogs with improved solubility and activity, and less toxicity. Several enzymes in pradimicin biosynthesis have been identified. We intend to characterize one of the key enzymes, PdmS, a putative glycosyltransferase, and to manipulate its gene to create novel, more efficacious pradimicin analogs. This project is funded for three years by the NIH NIAID (3 years). Methods: A gene knockout experiment was used to determine the role of PdmS in pradimicin production. Bio-synthetic precursors of pradimicin were subjected to bio-transformations in E. coli with recombinant genes for PdmS and another glycosyltransferase, OleD, to generate analogs with new sugar attachments. Analogs of pradimicin will be screened for bio-activity using standard microbroth dilution assay techniques. Confirmed results: The enzyme PdmS was identified and characterized as a glycosyltransferase. Expected results: newly created analogs of pradimicin exhibited minimal inhibitory concentrations of 10μg/mL against Candida albicans. Conclusion: Knockout of pdmS yielded the pradimicin aglycon, which confirmed the function of this glycosyltransferase and provides a start molecule for further structural modification to yield new analogs for bioactivity studies.