title: Novobiocin inhibits the self-splicing of the primary transcripts of T4 phage thymidylate synthase gene.
abstract: Effects of the antibiotic novobiocin on the self-splicing of primary transcripts of the phage T4 thymidylate synthase gene (td) have been investigated. Novobiocin at 10 mM concentration inhibited the splicing by about 5% but at 40 mM concentration the splicing rate was inhibited by about 50%. The novobiocin inhibition of the self-splicing reaction was not reversed even at a high concentration (200 microM) of guanosine. However, increasing the Mg(2+) ion concentrations up to 20 mM almost fully restored the splicing activity to the normal splicing level. The double reciprocal plot analysis demonstrated that novobiocin acts as a mixed noncompetitive inhibitor for the td intron RNA with a K (i) of 90 mM. The splicing inhibition by novobiocin was strongly dependent on Mg(2+) ion concentration, indicating electrostatic interactions with the td intron RNA. It is likely that the antibiotic novobiocin may interfere with the catalytic actions of Mg(2+) ion in the splicing reaction of the td intron RNA.
authors.affiliation: Department of Life Science, Dongguk University, Seoul, Korea.
authors.forename: Wi Su
authors.initials: WS
authors.lastname: Jung
authors.forename: Sook
authors.initials: S
authors.lastname: Shin
authors.forename: In Kook
authors.initials: IK
authors.lastname: Park
mesh_terms: D017122:Bacteriophage T4 / Q000235:genetics*; D015536:Down-Regulation / Q000187:drug effects; D007438:Introns; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008954:Models, Biological; D009675:Novobiocin / Q000494:pharmacology*; D012326:RNA Splicing / Q000187:drug effects*; D016337:RNA, Catalytic / Q000187:drug effects* / Q000378:metabolism; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D013940:Thymidylate Synthase / Q000235:genetics*; D013997:Time Factors
chemical_list: D016337:RNA, Catalytic; D012367:RNA, Viral; D009675:Novobiocin; D013940:Thymidylate Synthase; D008274:Magnesium