10.6084/m9.figshare.5777472.v1 Felix G. M. Ernst Felix G. M. Ernst Lieselotte Erber Lieselotte Erber Joana Sammler Joana Sammler Frank Jühling Frank Jühling Heike Betat Heike Betat Mario Mörl Mario Mörl Cold adaptation of tRNA nucleotidyltransferases: A tradeoff in activity, stability and fidelity Taylor & Francis Group 2018 Fidelity tradeoff error rate CCA-addition CCACCA tag polymerization fidelity psychrophilic RNA polymerase tRNA quality control 2018-01-11 09:40:18 Dataset https://tandf.figshare.com/articles/dataset/Cold_adaptation_of_tRNA_nucleotidyltransferases_A_tradeoff_in_activity_stability_and_fidelity/5777472 <p>Cold adaptation is an evolutionary process that has dramatic impact on enzymatic activity. Increased flexibility of the protein structure represents the main evolutionary strategy for efficient catalysis and reaction rates in the cold, but is achieved at the expense of structural stability. This results in a significant activity-stability tradeoff, as it was observed for several metabolic enzymes. In polymerases, however, not only reaction rates, but also fidelity plays an important role, as these enzymes have to synthesize copies of DNA and RNA as exact as possible. Here, we investigate the effects of cold adaptation on the highly accurate CCA-adding enzyme, an RNA polymerase that uses an internal amino acid motif within the flexible catalytic core as a template to synthesize the CCA triplet at tRNA 3′-ends. As the relative orientation of these residues determines nucleotide selection, we characterized how cold adaptation impacts template reading and fidelity. In a comparative analysis of closely related psychro-, meso-, and thermophilic enzymes, the cold-adapted polymerase shows a remarkable error rate during CCA synthesis <i>in vitro</i> as well as <i>in vivo</i>. Accordingly, CCA-adding activity at low temperatures is not only achieved at the expense of structural stability, but also results in a reduced polymerization fidelity.</p>