Functional equivalence of the uridine turn and the hairpin as building blocks of tertiary structure in the Neurospora VS ribozyme.
Mutational, kinetic, and chemical modification experiments show that one of the three-way helical junctions in the Neurospora VS ribozyme contains a uridine turn that is important for organizing the functional three-dimensional structure of this junction. Disruption of the uridine turn disrupts the structure of the junction and decreases the self-cleavage activity of the ribozyme; however, substitution of the uridine turn with a variety of different hairpins, thereby transforming the three-way junction into a four-way junction, maintains catalytic activity. Chemical modification structure probing reveals that both the native junction and the hairpin-containing junction support the same tertiary interactions required elsewhere in the ribozyme for catalysis. These observations show that functionally equivalent three-dimensional RNA structures can be built from different secondary structure elements.
Sood
V D
VD
Department of Molecular and Medical Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
Collins
R A
RA
D001483:Base Sequence; D004722:Endoribonucleases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009491:Neurospora / Q000201:enzymology* / Q000235:genetics*; D023282:Nuclease Protection Assays; D009690:Nucleic Acid Conformation; D016337:RNA, Catalytic / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D014529:Uridine / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D016337:RNA, Catalytic; D004722:Endoribonucleases; C438195:varkud satellite ribozyme; D014529:Uridine