This chapter describes 3' maturation and repair, with particular emphasis on the ribonucleases and tRNA nucleotidyltransferase, the enzymes that participate in these processes. All tRNA molecules are synthesized initially as tRNA precursors containing additional residues at their 5' and 3‘ termini that must be removed to generate active tRNAs. The strict requirement for an intact -C-C-A sequence for the proper functioning of tRNA necessitates specific and accurate processing machinery for 3' maturation and also a mechanism to repair tRNA molecules with faulty 3' termini. For precursors in which -C-C-A residues are already present (type-I precursors), 3' maturation would only require removal of residues following the mature terminus, either by exonucleolytic trimming or by a specific endonucleolytic cut following the 3' terminal adenosine. Such enzymes are known. In addition, there are differences in 3'-terminal structure between most prokaryotic and eukaryotic tRNA precursors that introduce an additional level of complexity to this process.
|Original language||English (US)|
|Number of pages||32|
|Journal||Progress in Nucleic Acid Research and Molecular Biology|
|State||Published - Jan 1 1990|
ASJC Scopus subject areas
- Molecular Biology