RNA 5'-triphosphatase, nucleoside triphosphatase, and guanylyltransferase activities of baculovirus LEF-4 protein Journal Article
| Authors: | Gross, C. H.; Shuman, S. |
| Article Title: | RNA 5'-triphosphatase, nucleoside triphosphatase, and guanylyltransferase activities of baculovirus LEF-4 protein |
| Abstract: | Autographa californica nuclear polyhedrosis virus late and very late mRNAs are transcribed by an RNA polymerase consisting of four virus-encoded polypeptides: LEF-8, LEF-9, LEF-4, and p47. The 464-amino-acid LEF-4 subunit contains the signature motifs of GTP:RNA guanylyltransferases (capping enzymes). Here, we show that the purified recombinant LEF-4 protein catalyzes two reactions involved in RNA cap formation. LEF-4 is an RNA 5'- triphosphatase that hydrolyzes the γ phosphate of triphosphate-terminated RNA and a guanylyltransferase that reacts with GTP to form a covalent protein-guanylate adduct. The RNA triphosphatase activity depends absolutely on a divalent cation; the cofactor requirement is satisfied by either magnesium or manganese. LEF-4 also hydrolyzes ATP to ADP and P(i) (K(m) = 43 μM ATP; V(max) = 30 s-1) and GTP to GDP and P(i). The LEF-4 nucleoside triphosphatase (NTPase) is activated by manganese or cobalt but not by magnesium. The RNA triphosphatase and NTPase activities of baculovirus LEF-4 resemble those of the vaccinia virus and Saccharomyces cerevisiae mRNA capping enzymes. We suggest that these proteins comprise a novel family of metal-dependent triphosphatases. |
| Keywords: | protein expression; nonhuman; animals; adenosine diphosphate; enzyme activity; acid anhydride hydrolases; evolution, molecular; methyltransferases; amino acid sequence; conserved sequence; molecular sequence data; sequence homology, amino acid; virus rna; protein purification; saccharomyces cerevisiae; rna caps; recombinant proteins; vaccinia virus; base sequence; dna primers; adenosine triphosphate; multienzyme complexes; guanosine triphosphate; hydrolysis; phosphoric monoester hydrolases; enzyme assay; viral proteins; rna polymerase; guanosine diphosphate; nucleotidyltransferases; baculovirus; nucleoside-triphosphatase; 5'-guanylic acid; priority journal; article; nucleopolyhedrovirus; polyhedrosis virus |
| Journal Title: | Journal of Virology |
| Volume: | 72 |
| Issue: | 12 |
| ISSN: | 0022-538X |
| Publisher: | American Society for Microbiology |
| Date Published: | 1998-12-01 |
| Start Page: | 10020 |
| End Page: | 10028 |
| Language: | English |
| PUBMED: | 9811740 |
| PROVIDER: | scopus |
| PMCID: | PMC110522 |
| DOI/URL: | |
| Notes: | Article -- Export Date: 12 December 2016 -- Source: Scopus |
