Poster abstracts

Poster number 81 submitted by Prabuddha Madubashitha

A study of aminoglycoside binding to 16S rRNA

Prabuddha Madubashitha (Department of Chemistry, Wayne State University, Detroit, MI 48202), Evan Jones (Department of Chemistry, Wayne State University, Detroit, MI 48202), Christine S. Chow (Department of Chemistry, Wayne State University, Detroit, MI 48202)

Abstract:
Despite the potency of aminoglycosides (AG), development of bacterial resistance and adverse side effects on human health including ototoxicity are the major challenges of using AGs as antibiotics. Modifying currently available AGs is a potential strategy in developing better antibiotics that maintain activity but with reduced anti-mitoribosomal binding and associated ototoxicity. Towards this end, knowledge of the binding of a particular AG to its target at the molecular level is important. The objective of our study was to determine the binding affinity and examine drug-induced structural changes of a modified AG, 4'-O-ethyl paromomycin, and helix 44 (h44) of the aminoacyl-tRNA site (A site) of 16S rRNA. By using both chemical footprinting and a fluorescence-based assay, 4'-O-ethylparomomycin, was shown to have affinity for both the bacterial ribosome and bacterial h44 construct. More importantly, 4'-O-ethyl paromomycin displays improved selectivity towards the bacterial A site compared to the corresponding mitochondrial construct in the fluorescence-based assay. This result supports the observed reduction of ototoxicity for 4'-O-ethyl paromomycin.1 NMR data suggest that 4'-O-ethyl paromomycin retains a similar binding mode to that of 4, 5-disubstituted AGs to the bacterial A-site rRNA. These results will lead to a better understanding of drug-rRNA interactions at the molecular level.

References:
Reference
1. Duscha, S., Boukari, H., Shcherbakov, D., Salian, S., Silva, S., Kendall, A., Kato, T., Akbergenov, R., Perez-fernandez, D., Bernet, B., Vaddi, S., Thommes, P., Schacht, J., Crich, D., Vasella, A., Böttger, E. C. MBio. 2014, 5, e01827-14

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