title: Non-competitive inhibition of group I intron RNA self-splicing by aminoglycoside antibiotics.
abstract: Aminoglycoside antibiotics inhibit self-splicing of group I intron RNA in vitro at concentrations as low as 10(-6) M. The sites of interaction and the mechanism of inhibition have yet to be determined. A comparative study of inhibition by different 2-deoxystreptamine analogues reveals structural features of the aminoglycoside antibiotics required for their interaction and effect on group I introns. Complete antibiotic inhibition of the two steps of splicing was not reversed at high concentrations of guanosine, indicating a non-competitive inhibition. A mutant group I intron in which the conserved guanosine nucleotide of the G-binding site had been replaced by an adenosine, was sensitive to the antibiotics providing direct evidence that the antibiotics do not interact with the G-binding site in the same way as the guanine base. In addition kinetic analyses of the self-splicing process in the presence of antibiotic inhibitors supported a non-competitive mechanism of the mixed type for inhibition of the ribozyme.
authors.affiliation: Institut für Mikrobiologie und Genetik, Universität Wien, Vienna, Austria.
authors.forename: U
authors.initials: U
authors.lastname: von Ahsen
authors.forename: J
authors.initials: J
authors.lastname: Davies
authors.forename: R
authors.initials: R
authors.lastname: Schroeder
mesh_terms: D000617:Aminoglycosides; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001665:Binding Sites; D002240:Carbohydrate Sequence; D006151:Guanosine / Q000378:metabolism; D006595:Hexosamines / Q000032:analysis; D007438:Introns / Q000502:physiology*; D007700:Kinetics; D008969:Molecular Sequence Data; D016296:Mutagenesis; D012326:RNA Splicing / Q000187:drug effects*; D016337:RNA, Catalytic / Q000037:antagonists & inhibitors; D016053:RNA, Protozoan / Q000235:genetics / Q000378:metabolism; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D016808:Tetrahymena thermophila / Q000378:metabolism
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D006595:Hexosamines; D016337:RNA, Catalytic; D016053:RNA, Protozoan; D012335:RNA, Ribosomal; D006151:Guanosine; C007265:2-deoxystreptamine