Peptide antibiotics of the tuberactinomycin family as inhibitors of group I intron RNA splicing.
The tuberactinomycins are a group of cyclic peptide antibiotics, which are potent inhibitors of prokaryotic protein synthesis. We report the inhibitory effect of viomycin, di-beta-lysyl-capreomycin IIA and tuberactinomycin A on group I intron self-splicing. They compete with the guanosine cofactor for the G-binding site located in the conserved core of the intron. They are 100-fold more active than all other competitive inhibitors described so far (dGTP, arginine or streptomycin), inhibiting splicing at concentrations between 10 and 50 microM. Mutation of the G-binding site leads to partial resistance, and the inhibitory effect of these drugs is dependent on Mg2+ concentration. This suggests that the tuberactinomycins have more than one contact site with the intron RNA: via the G-binding site and via additional contacts with the RNA backbone. Positioning the tuberactinomycins in the three-dimensional model of the td intron core suggests that the charged lysyl side-chain (R1) is in contact with the backbone of the P1 helix. Structure/function analyses with various tuberactinomycin analogues with different activities confirm the involvement of this sidechain in inhibition of group I self-splicing. The demonstration of a new class of splicing inhibitors, the peptide antibiotics, illustrates how antibiotics may interact with catalytic RNA.
Wank
H
H
Institut für Mikrobiologie und Genetik, Universität Wien, Vienna, Austria.
Rogers
J
J
Davies
J
J
Schroeder
R
R
D017122:Bacteriophage T4 / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D001667:Binding, Competitive; D002207:Capreomycin / Q000031:analogs & derivatives / Q000494:pharmacology; D004279:DNA, Viral / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000235:genetics; D004776:Enviomycin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D007438:Introns / Q000187:drug effects*; D008274:Magnesium / Q000494:pharmacology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D012326:RNA Splicing / Q000187:drug effects* / Q000235:genetics; D012367:RNA, Viral / Q000737:chemistry / Q000187:drug effects / Q000235:genetics; D013329:Structure-Activity Relationship; D014756:Viomycin / Q000494:pharmacology
D004279:DNA, Viral; D012367:RNA, Viral; D002207:Capreomycin; C033359:di-beta-lysyl capreomycin IIA; C015563:tuberactinomycin; D008274:Magnesium; D004776:Enviomycin; D014756:Viomycin