Structural insights into the stimulation of S. pombe Dnmt2 catalytic efficiency by the tRNA nucleoside queuosine.

ABSTRACT: Dnmt2 methylates cytosine at position 38 of tRNA^Asp in a variety of eukaryotic organisms. A correlation between the presence of the hypermodified nucleoside queuosine (Q) at position 34 of tRNA^Asp and the Dnmt2 dependent C38 methylation was recently found in vivo for S. pombe and D. discoideum. We demonstrate a direct effect of the Q-modification on the methyltransferase catalytic efficiency in vitro, as V_max/K_0.5 of purified S. pombe Dnmt2 shows an increase for in vitro transcribed tRNA^Asp containing Q34 to 6.27 ∗ 10^-3 s^-1 µM^-1 compared to 1.51 ∗ 10^-3 s^-1 µM^-1 for the unmodified substrate. Q34tRNA^Asp exhibits an only slightly increased affinity for Dnmt2 in c

SUBMITTER: Johannsson S 

PROVIDER: S-EPMC5995894 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature