Action spectra for UV- light induced RNA-RNA crosslinking in 16S ribosomal RNA in the ribosome.

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Date

2002-08-28

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Abstract

UV- light induced crosslinking has been used to study RNA structures since the 1970s. The idea behind the method is that if there is an interaction between two nucleotides in the RNA tertiary structure, either as a part of the same strand or as a part of intermolecular interaction, they sometime will form covalent bond or "crosslink" with each other upon exposure to the UV light. Importantly, these interactions seem to be specific, limited in number and the crosslinking efficiencies are sufficient to allow their use in monitoring conformational changes of macromolecules. The occurrence of crosslinks within macromolecules depends on a combination of factors, including the inherent photoreactivity of the nucleotides that are joined, the correct distance and geometrical arrangement of the nucleotides, the molecular dynamics at the site of the crosslink and the wavelength of UV light that is used for irradiation. In this work, action spectra for eight out of fifteen 16S rRNA crosslinks were determined. For six of the crosslinks the action spectra correspond to the absorption spectra of at least one of the participating nucleotides. For two of them: C967 x C1400 and C1402 x C1501 the absorption maximum differs from the spectra of cytidine in aqua solution. The spectra for the C1402 x C1501 crosslink may be shifted because C1402 is posttranscriptionally modified to m4Cm. This difference can also result from the influence of molecular environment at the absorption of nucleotides, participating in those crosslinks formation.

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Keywords

16S rRNA, crosslinks, Action spectra

Citation

Degree

MS

Discipline

Biochemistry

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