Transfer RNA conformation in solution investigated by isotope labeling

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Transfer RNA (tRNA) molecules play a crucial role in protein synthesis.
• The three-dimensional structure of tRNA is essential for its function.
• Understanding how molecular conformation affects biochemical reactions is vital.

Purpose of the Study:

• To investigate the influence of yeast tRNA(Phe) conformation on tritium incorporation into purine residues.
• To determine how molecular folding impacts the accessibility of specific purine sites for labeling.
• To explore the use of isotope labeling as a tool to monitor conformational changes.

Main Methods:

• Tritium incorporation assays were performed on yeast tRNA(Phe) in various conformational states (unfolded, partially folded, folded).
• Nucleic acid digestion using specific nucleases was employed to analyze labeled fragments.
• Radioactive fragment analysis was used to quantify tritium incorporation at specific purine sites.

Main Results:

• Tritium incorporation at the C-8 position of purines is highly dependent on tRNA(Phe) conformation.
• Unfolded tRNA incorporates tritium at a rate similar to free purine nucleotides.
• Folded tRNA shows reduced and sequence-position-dependent tritium labeling, correlating with structural data.

Conclusions:

• The conformation of yeast tRNA(Phe) significantly modulates the accessibility of purine residues to tritium labeling.
• Isotope labeling can serve as a sensitive probe to study tRNA folding, unfolding, and conformational dynamics.
• Labeling patterns provide insights into the structural organization of tRNA, distinguishing between surface-exposed and internally masked residues.