CCA-addition in the cold: Structural characterization of the psychrophilic CCA-adding enzyme from the permafrost bacterium Planococcus halocryophilus

• Published in: Computational and Structural Biotechnology Journal
• Main Authors: de Wijn, Raphaël, Rollet, Kévin, Ernst, Felix G.M., Wellner, Karolin, Betat, Heike, Mörl, Mario, Sauter, Claude
• Other Authors: Architecture et Réactivité de l'ARN (ARN), Institut de biologie moléculaire et cellulaire (IBMC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: [SDV]Life Sciences [q-bio]; [SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry; Molecular Biology/Molecular biology; [SDV.BBM]Life Sciences [q-bio]/Biochemistry; Molecular Biology; Arctic; permafrost
• Online Access: https://hal.archives-ouvertes.fr/hal-03419675; https://hal.archives-ouvertes.fr/hal-03419675/document; https://hal.archives-ouvertes.fr/hal-03419675/file/Sauter%20C%20-CCA-addition%20in%20the%20cold-%20Structural%20characterization%20of%20the%20psychrophilic%20CCA-adding%20enzyme%20from%20the%20permafrost%20bacterium%20Planococcus%20halocryophilus.pdf; https://doi.org/10.1016/j.csbj.2021.10.018

International audience CCA-adding enzymes are highly specific RNA polymerases that add and maintain the sequence CC A at tRNA 3'-ends. Recently, we could reveal that cold adaptation of such a polymerase is not only achieved at the expense of enzyme stability, but also at the cost of polymerization fidelity. Enzymes from psychrophilic organisms usually show an increased structural flexibility to enable catalysis at low temperatures. Here, polymerases face a dilemma, as there is a discrepancy between the need for a tightly controlled flexibility during polymerization and an increased flexibility as strategy for cold adaptation. Based on structural and biochemical analyses, we contribute to clarify the cold adaptation strategy of the psychrophilic CCA-adding enzyme from Planococcus halocryophilus, a gram-positive bacterium thriving in the arctic permafrost at low temperatures down to À15°C. A comparison with the closely related enzyme from the thermophilic bacterium Geobacillus stearothermophilus reveals several features of cold adaptation-a significantly reduced amount of alpha-helical elements in the C-terminal tRNA-binding region and a structural adaptation in one of the highly conserved catalytic core motifs located in the N-terminal catalytic core of the enzyme.