Effect of sequence mutations on the higher order structure of the yeast 5 S rRNA.
Mutant yeast ribosomal 5 S RNAs were probed by enzymatic cleavage and chemical reactivity to define further the higher order structure. Mutations that destabilized helix IV resulted in an altered tertiary structure in which a reduced reactivity to ethylnitrosourea at U90 and G91 could be correlated with greater enzymatic and Fe(II)-EDTA cleavages in helices II and V. The results provide direct evidence for, and a further definition of, a structural juxtaposition between helix II and the end of helix IV and indicate that, in contrast to earlier suggestions, the remaining tertiary structure is sufficiently stable to prevent "pseudoknot-like" interactions between helices III and IV. The data are fully consistent with the "lollipop" model of the tertiary structure.
Van Ryk
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Department of Molecular Biology and Genetics, University of Guelph, Ontario, Canada.
Nazar
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D001483:Base Sequence; D004492:Edetic Acid / Q000494:pharmacology; D005038:Ethylnitrosourea / Q000494:pharmacology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009690:Nucleic Acid Conformation; D012331:RNA, Fungal / Q000737:chemistry / Q000187:drug effects / Q000235:genetics*; D012341:RNA, Ribosomal, 5S / Q000737:chemistry / Q000187:drug effects / Q000235:genetics*; D012260:Ribonucleases / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics*
D012331:RNA, Fungal; D012341:RNA, Ribosomal, 5S; D004492:Edetic Acid; D012260:Ribonucleases; D005038:Ethylnitrosourea