The relationship between aminoglycosides' RNA binding proclivity and their antiplasmid effect on an IncB plasmid.
Bacteria routinely become resistant to antibiotics through the uptake of plasmids that encode resistance-mediating proteins. Such plasmid-based resistance is seen extensively in clinical settings and has been documented for a wide variety of bacterial infections from both Gram-positive and Gram-negative organisms. We recently reported that a small molecule could be used to mimic a natural process of plasmid elimination, called plasmid incompatibility, and that the addition of this compound causes elimination of an IncB plasmid from E. coli and a subsequent resensitization to antibiotics [DeNap, Thomas, Musk, and Hergenrother (2004) J. Am. Chem. Soc. 126, 15402-15404]. Described herein is a further substantiation and validation of the notion that plasmid incompatibility can be mimicked with small molecules that bind to important RNA targets controlling plasmid replication. In this study, the dissociation constant and stoichiometry of RNA binding are determined for 12 aminoglycosides with stem-loop I (SLI) of the IncB replication machinery. Importantly, it is found that compounds that do not bind to this RNA replication control element fail to induce plasmid loss in vivo, whereas those that do bind to the RNA typically cause measurable plasmid loss. These results highlight the potential for targeting key RNA regions for induction of plasmid loss and the subsequent resensitization of bacteria to antibiotics.
Thomas
Jason R
JR
Department of Chemistry, Roger Adams Laboratory, University of Illinois, Urbana, Illinois 61801, USA.
DeNap
Johna C B
JC
Wong
Margaret L
ML
Hergenrother
Paul J
PJ
D000617:Aminoglycosides / Q000737:chemistry* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D004265:DNA Helicases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D006921:Hygromycin B / Q000737:chemistry / Q000378:metabolism; D018716:Molecular Mimicry / Q000235:genetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011815:R Factors / Q000037:antagonists & inhibitors* / Q000235:genetics* / Q000378:metabolism; D012329:RNA, Bacterial / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000198:Spectinomycin / Q000737:chemistry / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D015534:Trans-Activators / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
D000617:Aminoglycosides; D004268:DNA-Binding Proteins; D012329:RNA, Bacterial; D015534:Trans-Activators; C045264:replication initiator protein; D006921:Hygromycin B; D000198:Spectinomycin; D004265:DNA Helicases