title: tRNA(Phe) binds aminoglycoside antibiotics.
abstract: Aminoglycoside antibiotics have recently been found to bind to a variety of unrelated RNA molecules, including sequences that are important for retroviral replication. We report the binding of neomycin B, kanamycin A, and Neo-Neo (a synthetic neomycin-neomycin dimer) to tRNA(Phe). Using thermal denaturation studies, fluorescence spectroscopy, Pb2+-mediated tRNA(Phe) cleavage, and gel mobility shift assays, we have established that aminoglycosides interact with yeast tRNA(Phe) and are likely to induce a conformational change. Thermal denaturation studies revealed that aminoglycosides have a substantial stabilizing effect on tRNA(Phe) secondary and tertiary structures, much greater than the stabilization effect of spermine, an unstructured polyamine. Aminoglycoside-induced inhibition of Pb2+-mediated tRNA(Phe) cleavage yielded IC50 values of: 5 microM for Neo-Neo, 100 microM for neomycin B, > 1 mM for kanamycin A, and > 10 mM for spermine. Enzymatic and chemical footprinting indicate that the anticodon stem as well as the junction of the TpsiC and D loops are preferred aminoglycoside binding sites.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla 92093-0358, USA.
authors.forename: S R
authors.initials: SR
authors.lastname: Kirk
authors.forename: Y
authors.initials: Y
authors.lastname: Tor
mesh_terms: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006358:Hot Temperature; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012360:RNA, Transfer, Phe / Q000737:chemistry / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D012360:RNA, Transfer, Phe