Yeast and viral RNA 5' triphosphatases comprise a new nucleoside triphosphatase family Journal Article
| Authors: | Ho, C. K.; Pei, Y.; Shuman, S. |
| Article Title: | Yeast and viral RNA 5' triphosphatases comprise a new nucleoside triphosphatase family |
| Abstract: | Saccharomyces cerevisiae Cet1p catalyzes the first step of mRNA capping, the hydrolysis of the γ phosphate of triphosphate-terminated RNA to form a 5' diphosphate end. The RNA triphosphatase activity of Cet1p is magnesium- dependent and has a turnover number of 1 s-1. Here we show that purified recombinant Cet1p possesses a robust ATPase activity (K(m) = 2.8 μM; V(max) = 25 s-1) in the presence of manganese. Cobalt is also an effective cofactor, but magnesium, calcium, copper, and zinc are not. Cet1p displays broad specificity in converting ribonucleoside triphosphates and deoxynucleoside triphosphates to their respective diphosphates. The manganese- and cobalt-dependent nucleoside triphosphatase of Cet1p resembles the nucleoside triphosphatase activities of the baculovirus LEF-4 and vaccinia virus D1 capping enzymes. Cet1p, LEF-4, and D1 share three collinear sequence motifs. Mutational analysis establishes that conserved glutamate and arginine side chains within these motifs are essential for the RNA triphosphatase and ATPase activities of Cet1p in vitro and for Cet1p function in vivo. These findings are in accord with the effects of single alanine mutations at analogous positions of vaccinia capping enzyme. We suggest that the metal-dependent RNA triphosphatases encoded by yeast and DNA viruses comprise a novel family of phosphohydrolase enzymes with a common active site. |
| Keywords: | gene mutation; nonhuman; genetic analysis; protein domain; amino acid substitution; enzyme activation; nucleoside triphosphatase; enzyme activity; acid anhydride hydrolases; cloning, molecular; methyltransferases; kinetics; virus rna; saccharomyces cerevisiae; dna viruses; escherichia coli; recombinant proteins; vaccinia virus; mutagenesis, site-directed; yeast; alanine; cobalt; protein family; multienzyme complexes; adenosine triphosphatases; phosphoric monoester hydrolases; viral proteins; enzyme active site; cations, divalent; vaccinia; rna capping; nucleotidyltransferases; manganese; chlorides; baculovirus; baculoviridae; unidentified baculovirus; priority journal; article; manganese compounds; saccharomyces cerevisiae virus l-a (l1) |
| Journal Title: | Journal of Biological Chemistry |
| Volume: | 273 |
| Issue: | 51 |
| ISSN: | 0021-9258 |
| Publisher: | American Society for Biochemistry and Molecular Biology |
| Date Published: | 1998-12-18 |
| Start Page: | 34151 |
| End Page: | 34156 |
| Language: | English |
| DOI: | 10.1074/jbc.273.51.34151 |
| PUBMED: | 9852075 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | Article -- Export Date: 12 December 2016 -- Source: Scopus |
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