Substrate Affinity Versus Catalytic Efficiency: Ancestral Sequence Reconstruction of tRNA Nucleotidyltransferases Solves an Enzyme Puzzle.

ABSTRACT: In tRNA maturation, CCA-addition by tRNA nucleotidyltransferase is a unique and highly accurate reaction. While the mechanism of nucleotide selection and polymerization is well understood, it remains a mystery why bacterial and eukaryotic enzymes exhibit an unexpected and surprisingly low tRNA substrate affinity while they efficiently catalyze the CCA-addition. To get insights into the evolution of this high-fidelity RNA synthesis, the reconstruction and characterization of ancestral enzymes is a versatile tool. Here, we investigate a reconstructed candidate of a 2 billion years old CCA-adding enzyme from Gammaproteobacteria and compare it to the corresponding modern enzyme of Escherichia coli. We show that the ancestral candidate catalyzes an error-free CCA-addition, but has a much higher

SUBMITTER: Hager M 

PROVIDER: S-EPMC9728577 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature