AN RNA 5'-TRIPHOSPHATASE RELATED TO THE PROTEIN-TYROSINE PHOSPHATASES

Citation
T. Takagi et al., AN RNA 5'-TRIPHOSPHATASE RELATED TO THE PROTEIN-TYROSINE PHOSPHATASES, Cell, 89(6), 1997, pp. 867-873
Citations number
26
Categorie Soggetti
Biology,"Cell Biology
Journal title
CellACNP
ISSN journal
00928674
Volume
89
Issue
6
Year of publication
1997
Pages
867 - 873
Database
ISI
SICI code
0092-8674(1997)89:6<867:AR5RTT>2.0.ZU;2-G
Abstract
mRNA capping requires the sequential action of three enzymatic activit ies: RNA triphosphatase, guanylyltransferase, and methyltransferase. H ere we characterize a gene (GEL-I) 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 guanylyltransferases. The N -terminal domain of CEL-1 has RNA tri phosphatase activity. Surprising ly, this domain does not resemble the vaccinia virus capping enzyme bu t does have significant sequence similarity to the protein tyrosine ph osphatase (PTP) enzyme family. However, CEL-1 has no detectable PTP ac tivity. The mechanism of the RNA triphosphatase is similar to that of PTPs: the active site contains a conserved nucleophilic cysteine requi red for activity. These results broaden the superfamily of PTP-like ph osphatases to include enzymes with RNA substrates.