Mapping tRNA structure in solution using double-strand-specific ribonuclease V1 from cobra venom

Area of Science:

• Molecular Biology
• Biochemistry
• Structural Biology

Background:

• Transfer RNAs (tRNAs) are crucial for protein synthesis, with their function dependent on specific three-dimensional structures.
• Mapping base-paired stems in tRNAs is essential for understanding their structure-function relationships.

Purpose of the Study:

• To develop and validate a method for mapping all base-paired stems in elongation and initiator tRNAs.
• To investigate the substrate specificity of ribonuclease V1 in relation to tRNA structure.

Main Methods:

• Partial digestion of 32P-end-labeled RNA with double-strand-specific ribonuclease V1 under physiological conditions.
• Electrophoretic fractionation of resultant RNA fragments by size using polyacrylamide gel electrophoresis in 90% formamide.
• Comparative analysis of V1-generated fragments with those produced by Neurospora endonuclease and base-specific ribonucleases for definitive nucleotide location.

Main Results:

• Ribonuclease V1 cleaves exclusively within every base-paired stem of yeast tRNAPhe and E. coli tRNAfMet.
• Nuclease V1 demonstrates the ability to digest paired nucleotides not solely reliant on standard Watson-Crick base-pairing.
• Cleavage within wobble base-pairs and nucleotides involved in tertiary base-base hydrogen bonding was observed in yeast tRNAPhe.

Conclusions:

• The described method effectively maps all base-paired stems in both elongation and initiator tRNAs.
• Ribonuclease V1 is a valuable tool for probing tRNA secondary and tertiary structures, including non-canonical base pairs.
• This technique provides precise structural information crucial for understanding tRNA function in translation.