In vitro substrate specificities of 3'-5' polymerases correlate with biological outcomes of tRNA 5'-editing reactions

FEBS Lett. 2015 Jul 22;589(16):2124-30. doi: 10.1016/j.febslet.2015.06.028. Epub 2015 Jul 2.

Abstract

Protozoan mitochondrial tRNAs (mt-tRNAs) are repaired by a process known as 5'-editing. Mt-tRNA sequencing revealed organism-specific patterns of editing G-U base pairs, wherein some species remove G-U base pairs during 5'-editing, while others retain G-U pairs in the edited tRNA. We tested whether 3'-5' polymerases that catalyze the repair step of 5'-editing exhibit organism-specific preferences that explain the treatment of G-U base pairs. Biochemical and kinetic approaches revealed that a 3'-5' polymerase from Acanthamoeba castellanii tolerates G-U wobble pairs in editing substrates much more readily than several other enzymes, consistent with its biological pattern of editing.

Keywords: 3′–5′ polymerase; Acanthamoeba castellanii; Dictyostelium discoideum; Mitochondrial tRNA; Thg1-like protein; tRNA editing.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acanthamoeba castellanii / enzymology*
  • Acanthamoeba castellanii / metabolism
  • Dictyostelium / enzymology
  • Dictyostelium / metabolism
  • Electrophoresis, Polyacrylamide Gel
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • Isotope Labeling
  • Kinetics
  • Mitochondria / enzymology*
  • Mitochondria / metabolism
  • Models, Molecular
  • Phosphorus Radioisotopes
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism*
  • RNA Editing*
  • RNA Nucleotidyltransferases / genetics
  • RNA Nucleotidyltransferases / metabolism*
  • RNA, Protozoan / chemistry
  • RNA, Protozoan / metabolism*
  • RNA, Transfer / chemistry
  • RNA, Transfer / metabolism*
  • RNA, Transfer, Ile / chemistry
  • RNA, Transfer, Ile / metabolism
  • Recombinant Proteins / metabolism
  • Species Specificity
  • Substrate Specificity

Substances

  • Isoenzymes
  • Phosphorus Radioisotopes
  • Protozoan Proteins
  • RNA, Protozoan
  • RNA, Transfer, Ile
  • Recombinant Proteins
  • RNA, Transfer
  • RNA Nucleotidyltransferases
  • tRNA nucleotidyltransferase