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An ultraviolet light-induced crosslink in yeast tRNA(Phe)
L S Behlen1, J R Sampson, O C Uhlenbeck
1Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309-0215.
Nucleic Acids Research
|August 11, 1992
Summary
UV light causes an intramolecular crosslink in yeast transfer RNA (tRNA) between specific bases. This crosslinking reaction requires the RNA's correct three-dimensional structure.
Area of Science:
- Molecular Biology
- Biochemistry
- Structural Biology
Background:
- Yeast transfer RNA (tRNA) plays a crucial role in protein synthesis.
- Understanding tRNA structure and function is vital for molecular biology research.
Purpose of the Study:
- To investigate the formation and nature of UV-induced intramolecular crosslinks in yeast tRNA(Phe).
- To determine the specific sites of crosslinking and the structural requirements for this reaction.
Main Methods:
- Irradiation of yeast tRNA(Phe) with UV light (260 nM).
- Mapping of the intramolecular crosslink site.
- Analysis of photo-reversibility and photo adducts.
- Evaluation of crosslinking efficiency in tRNA mutants.
Main Results:
- An intramolecular crosslink was identified between cytidine-48 (C48) in the variable loop and uridine-59 (U59) in the T loop of yeast tRNA(Phe).
- The crosslink product is likely a cytidine-uridine cyclobutane dimer, supported by photo-reversibility and lack of fluorescent adducts.
- The formation of this crosslink is dependent on the correct tertiary structure of the tRNA.
Conclusions:
- UV irradiation induces a specific crosslink in yeast tRNA(Phe) at the C48-U59 position.
- The reaction mechanism involves cyclobutane dimer formation.
- The tertiary structure of tRNA is essential for efficient UV-induced crosslinking.