Poster abstracts
Poster number 159 submitted by Hongkun Zhu
Functional characterization of derivatives of the aminoglycoside tobramycin
Hongkun Zhu (Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA), Keith D. Green (Department of Pharmaceutical Sciences, University of Kentucky, Lexingon, KY, 40536, USA), Sylvie Garneau-Tsodikova (Department of Pharmaceutical Sciences, University of Kentucky, Lexingon, KY, 40536, USA), Kurt Fredrick (Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA)
Abstract:
Emergence of resistance to antibiotics has become a serious problem in health care. In efforts to find ways to evade the resistance mechanisms, numerous derivatives of the aminoglycoside tobramycin (TOB), substituted at the 6” position of ring III, were made. Here, these TOB variants are characterized with respect to their mode of action, by employing 16S rRNA mutation A1408G, which lies at the primary aminoglycoside binding site in helix h44 of the small subunit. We tested the ability of each to inhibit (i) growth of E. coli strain Δ7 prrn (WT), (ii) growth of aminoglycoside- resistant E. coli strain Δ7 prrn (A1408G), (iii) translocation in WT ribosomes, and (iv) translocation in A1408G ribosomes. Based on the data obtained, the variants fall into different functional classes. Those in class A, like the parental TOB, act through the primary h44 site of ribosome. Some of them are potent inhibitors and may be potential candidates for clinical use. Other derivatives gain novel properties compared to parental tobramycin. For example, compounds 3,4,5,11,16,17 inhibit AMV reverse transcriptase, while compound 6 can promote mRNA secondary structure formation in the absence of ribosomes. A subset of compounds cause cell lysis (1), implicating the membrane as a cellular target in these cases. These data provide insight into the inhibition of translation and growth by aminoglycosides antibiotics.
References:
I. M. Herzog, K. D. Green, Y. Berkov-Zrihen, M. Feldman, R. R. Vidavski, A. Eldar-Boock, R. Satchi-Fainaro, A. Eldar, S. Garneau-Tsodikova, and M. Fridman, Angew. Chem. Int. Ed.2012, 51, 5652.
Keywords: aminoglycoside, ribosome, h44