Unknown

Dataset Information

0

Evolution of tRNA nucleotidyltransferases: a small deletion generated CC-adding enzymes.


ABSTRACT: CCA-adding enzymes are specialized polymerases that add a specific sequence (C-C-A) to tRNA 3' ends without requiring a nucleic acid template. In some organisms, CCA synthesis is accomplished by the collaboration of evolutionary closely related enzymes with partial activities (CC and A addition). These enzymes carry all known motifs of the catalytic core found in CCA-adding enzymes. Therefore, it is a mystery why these polymerases are restricted in their activity and do not synthesize a complete CCA terminus. Here, a region located outside of the conserved motifs was identified that is missing in CC-adding enzymes. When recombinantly introduced from a CCA-adding enzyme, the region restores full CCA-adding activity in the resulting chimera. Correspondingly, deleting the region in a CCA-adding enzyme abolishes the A-incorporating activity, also leading to CC addition. The presence of the deletion was used to predict the CC-adding activity of putative bacterial tRNA nucleotidyltransferases. Indeed, two such enzymes were experimentally identified as CC-adding enzymes, indicating that the existence of the deletion is a hallmark for this activity. Furthermore, phylogenetic analysis of identified and putative CC-adding enzymes indicates that this type of tRNA nucleotidyltransferases emerged several times during evolution. Obviously, these enzymes descend from CCA-adding enzymes, where the occurrence of the deletion led to the restricted activity of CC addition. A-adding enzymes, however, seem to represent a monophyletic group that might also be ancestral to CCA-adding enzymes. Yet, experimental data indicate that it is possible that A-adding activities also evolved from CCA-adding enzymes by the occurrence of individual point mutations.

SUBMITTER: Neuenfeldt A 

PROVIDER: S-EPMC2430343 | BioStudies | 2008-01-01

REPOSITORIES: biostudies

Similar Datasets

1000-01-01 | S-EPMC3248509 | BioStudies
2020-01-01 | S-EPMC7014341 | BioStudies
2017-11-03 | GSE98874 | GEO
2020-01-01 | S-EPMC7432833 | BioStudies
2018-01-01 | S-EPMC5785979 | BioStudies
1000-01-01 | S-EPMC4538823 | BioStudies
1000-01-01 | S-EPMC1765476 | BioStudies
2015-01-01 | S-EPMC4615804 | BioStudies
2019-01-01 | S-EPMC6468291 | BioStudies
2010-01-01 | S-EPMC3087442 | BioStudies