Preferential binding of yeast tRNA ligase to pre-tRNA substrates.

AUTOR(ES)

Apostol, B L

RESUMO

Joining of tRNA halves during splicing in extracts of Saccharomyces cerevisiae requires each of the three enzymatic activities associated with the tRNA ligase polypeptide. Joining is most efficient for tRNA as opposed to oligonucleotide substrates and is sensitive to single base changes at a distance from splice sites suggesting considerable specificity. To examine the basis for this specificity, binding of ligase to labeled RNA substrates was measured by native gel electrophoresis. Ligase bound tRNA halves with an association constant 1600-fold greater than that for a nonspecific RNA. Comparison of binding of a series of tRNA processing intermediates revealed that tRNA-structure, particularly in the region around the splice sites, contributes to specific binding. Finally, the ligase was shown to form multiple, discrete complexes with tRNA substrates. The basis for recognition by ligase and its role in a tRNA processing pathway are discussed.

Documentos Relacionados

• Possibility of Cytoplasmic pre-tRNA Splicing: the Yeast tRNA Splicing Endonuclease Mainly Localizes on the Mitochondria
• Yeast nucleoporin mutants are defective in pre-tRNA splicing.
• Pleiotropic effect of a point mutation in the yeast SUP4-o tRNA gene: in vivo pre-tRNA processing in S. cerevisiae.
• Non-enzymatic excision of pre-tRNA introns?
• Isolation of a yeast gene involved in species-specific pre-tRNA processing.