Adaptation of the Romanomermis culicivorax CCA-Adding Enzyme to Miniaturized Armless tRNA Substrates.

ABSTRACT: The mitochondrial genome of the nematode Romanomermis culicivorax encodes for miniaturized hairpin-like tRNA molecules that lack D- as well as T-arms, strongly deviating from the consensus cloverleaf. The single tRNA nucleotidyltransferase of this organism is fully active on armless tRNAs, while the human counterpart is not able to add a complete CCA-end. Transplanting single regions of the Romanomermis enzyme into the human counterpart, we identified a beta-turn element of the catalytic core that-when inserted into the human enzyme-confers full CCA-adding activity on armless tRNAs. This region, originally identified to position the 3'-end of the tRNA primer in the catalytic core, dramatically increases the enzyme's substrate affinity. While conventional tRNA substrates bind

SUBMITTER: Hennig O 

PROVIDER: S-EPMC7730189 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature