Publications

• Characterization of the Saccharomyces cerevisiae cyclic nucleotide phosphodiesterase involved in the metabolism of ADP-ribose 1',2'-cyclic phosphate.

  Nasr F., Filipowicz W.

  ADP-ribose 1",2"-cyclic phosphate (Appr>p) is produced in yeast and other eukaryotes as a consequence of tRNA splicing. This molecule is converted to ADP-ribose 1"-phosphate (Appr-1"p) by the action of the cyclic nucleotide phosphodiesterase (CPDase). Comparison of the previously cloned CPDase fro ... >> More

  ADP-ribose 1",2"-cyclic phosphate (Appr>p) is produced in yeast and other eukaryotes as a consequence of tRNA splicing. This molecule is converted to ADP-ribose 1"-phosphate (Appr-1"p) by the action of the cyclic nucleotide phosphodiesterase (CPDase). Comparison of the previously cloned CPDase from Arabidopsis with proteins having related cyclic phosphodiesterase or RNA ligase activities revealed two histidine-containing tetrapeptides conserved in these enzyme families. Using the consensus phosphodiesterase signature, we have identified the yeast Saccharomyces cerevisiae open reading frame YGR247w as encoding CPDase. The bacterially expressed yeast protein, named Cpd1p, is able to hydrolyze Appr>p to Appr-1"p. Moreover, as with the previously characterized Arabidopsis and wheat CPDases, Cpd1p hydrolyzes nucleosides 2',3'-cyclic phosphates (N>p) to nucleosides 2'-phosphates. Apparent K (m)values for Appr>p, A>p, U>p, C>p and G>p are 0.37, 4.97, 8.91, 12.18 and 14.29 mM, respectively. Site-directed mutagenesis of individual amino acids within the two conserved tetrapeptides showed that H(40)and H(150)residues are essential for CPDase activity. Deletion analysis has indicated that the CPD1 gene is not important for cellular viability. Likewise, overexpression of Cpd1p had no effect on yeast growth. These results do not implicate an important role for Appr>p or Appr-1"p in yeast cells grown under standard laboratory conditions. << Less

  Nucleic Acids Res. 28:1676-1683(2000) [PubMed] [EuropePMC]

  This publication is cited by 5 other entries.

• The HD domain of the Escherichia coli tRNA nucleotidyltransferase has 2',3'-cyclic phosphodiesterase, 2'-nucleotidase, and phosphatase activities.

  Yakunin A.F., Proudfoot M., Kuznetsova E., Savchenko A., Brown G., Arrowsmith C.H., Edwards A.M.

  In all mature tRNAs, the 3'-terminal CCA sequence is synthesized or repaired by a template-independent nucleotidyltransferase (ATP(CTP):tRNA nucleotidyltransferase; EC 2.7.7.25). The Escherichia coli enzyme comprises two domains: an N-terminal domain containing the nucleotidyltransferase activity ... >> More

  In all mature tRNAs, the 3'-terminal CCA sequence is synthesized or repaired by a template-independent nucleotidyltransferase (ATP(CTP):tRNA nucleotidyltransferase; EC 2.7.7.25). The Escherichia coli enzyme comprises two domains: an N-terminal domain containing the nucleotidyltransferase activity and an uncharacterized C-terminal HD domain. The HD motif defines a superfamily of metal-dependent phosphohydrolases that includes a variety of uncharacterized proteins and domains associated with nucleotidyltransferases and helicases from bacteria, archaea, and eukaryotes. The C-terminal HD domain in E. coli tRNA nucleotidyltransferase demonstrated Ni(2+)-dependent phosphatase activity toward pyrophosphate, canonical 5'-nucleoside tri- and diphosphates, NADP, and 2'-AMP. Assays with phosphodiesterase substrates revealed surprising metal-independent phosphodiesterase activity toward 2',3'-cAMP, -cGMP, and -cCMP. Without metal or in the presence of Mg(2+), the tRNA nucleotidyltransferase hydrolyzed 2',3'-cyclic substrates with the formation of 2'-nucleotides, whereas in the presence of Ni(2+), the protein also produced some 3'-nucleotides. Mutations at the conserved His-255 and Asp-256 residues comprising the C-terminal HD domain of this protein inactivated both phosphodiesterase and phosphatase activities, indicating that these activities are associated with the HD domain. Low concentrations of the E. coli tRNA (10 nm) had a strong inhibiting effect on both phosphatase and phosphodiesterase activities. The competitive character of inhibition by tRNA suggests that it might be a natural substrate for these activities. This inhibition was completely abolished by the addition of Mg(2+), Mn(2+), or Ca(2+), but not Ni(2+). The data suggest that the phosphohydrolase activities of the HD domain of the E. coli tRNA nucleotidyltransferase are involved in the repair of the 3'-CCA end of tRNA. << Less

  J. Biol. Chem. 279:36819-36827(2004) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.