| Autor: |
Hargittai MR; Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis 55455, USA., Musier-Forsyth K |
| Jazyk: |
angličtina |
| Zdroj: |
RNA (New York, N.Y.) [RNA] 2000 Nov; Vol. 6 (11), pp. 1672-80. |
| DOI: |
10.1017/s135583820000128x |
| Abstrakt: |
Lanthanide metals such as terbium have previously been shown to be useful for mapping metal-binding sites in RNA. Terbium binds to the same sites on RNA as magnesium, however, with a much higher affinity. Thus, low concentrations of terbium ions can easily displace magnesium and promote phosphodiester backbone scission. At higher concentrations, terbium cleaves RNA in a sequence-independent manner, with a preference for single-stranded, non-Watson-Crick base-paired regions. Here, we show that terbium is a sensitive probe of human tRNALys,3 tertiary structure and folding. When 1 microM tRNA is used, the optimal terbium ion concentration for detecting Mg2+-induced tertiary structural changes is 50-60 microM. Using these concentrations of RNA and terbium, a magnesium-dependent folding transition with a midpoint (KMg) of 2.6 mM is observed for unmodified human tRNALys,3. At lower Tb3+ concentrations, cleavage is restricted to nucleotides that constitute specific metal-binding pockets. This small chemical probe should also be useful for detecting protein induced structural changes in RNA. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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