An RNA 5'-triphosphatase related to the protein tyrosine phosphatases

Toshimitsu Takagi, Christine R. Moore, Felix Diehn, Stephen Buratowski

Research output: Contribution to journalArticlepeer-review

99 Scopus citations


mRNA capping requires the sequential action of three enzymatic activities: RNA triphosphatase, guanylyltransferase, and methyltransferase. Here we characterize a gene (CEL-1) believed to encode the C. elegans capping enzyme. CEL-1 has a C-terminal domain containing motifs found in yeast and vaccinia virus capping enzyme guenylyltransferases. The N-terminal domain of CEL-1 has RNA triphosphatase activity. Surprisingly, this domain does not resemble the vaccinia virus capping enzyme but does have significant sequence similarity to the protein tyrosine phosphatase (PTP) enzyme family. However, CEL-1 has no detectable PTP activity. The mechanism of the RNA triphosphatase is similar to that of PTPs: the active site contains a conserved nucleophilic cysteine required for activity. These results broaden the superfamily of PTP- like phosphatases to include enzymes with RNA substrates.

Original languageEnglish (US)
Pages (from-to)867-873
Number of pages7
Issue number6
StatePublished - Jun 13 1997

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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