Synthesis of the CCA end of essential tRNAs is performed either by CCA-adding enzymes
or as a collaboration between enzymes restricted to CC- and A-incorporation. While the occurrence
of such tRNA nucleotidyltransferases with partial activities seemed to be restricted to Bacteria,
the first example of such split CCA-adding activities was reported in Schizosaccharomyces pombe.
Here, we demonstrate that the choanoflagellate Salpingoeca rosetta also carries CC- and A-adding
enzymes. However, these enzymes have distinct evolutionary origins. Furthermore, the restricted
activity of the eukaryotic CC-adding enzymes has evolved in a different way compared to their
bacterial counterparts. Yet, the molecular basis is very similar, as highly conserved positions within
a catalytically important flexible loop region are missing in the CC-adding enzymes. For both the
CC-adding enzymes from S. rosetta as well as S. pombe, introduction of the loop elements from closely
related enzymes with full activity was able to restore CCA-addition, corroborating the significance of
this loop in the evolution of bacterial as well as eukaryotic tRNA nucleotidyltransferases. Our data
demonstrate that partial CC- and A-adding activities in Bacteria and Eukaryotes are based on the
same mechanistic principles but, surprisingly, originate from different evolutionary events.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:89302 |
| Date | 26 January 2024 |
| Creators | Erber, Lieselotte, Franz, Paul, Betat, Heike, Prohaska, Sonja, Mörl, Mario |
| Publisher | MDPI |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:article, info:eu-repo/semantics/article, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 462 |
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