Enzymatic conversion of 5'-phosphate-terminated RNA to 5'-di- and triphosphate-terminated RNA.
We have isolated from vaccinia virus cores an enzyme, 5'-phosphate-polyribonucleotide kinase, that in the presence of ATP and Mg2+ catalyzes the conversion of 5'-phosphate and 5'-diphosphate termini of RNA to the 5'-triphosphate species. With the exception of dATP, other nucleoside triphosphates were inactive as phosphate donors; activity with dATP was 10% of that observed with ATP. The purified enzyme did not phosphorylate 5'-hydroxyl- or 5'-monophosphate-terminated polydeoxyribonucleotides, although a variety of 5'- monophosphate-terminated RNA chains were active as phosphate acceptors. By using a coupled system of 5'-phosphate-polyribonucleotide kinase and guanylyltransferase in the presence of ATP, GTP, Mg2+, and S-adenosylmethionine, capping of 5'-P-, 5'-PP-, and 5'-PPP-RNA was demonstrated; in the absence of 5'-phosphate-polyribonucleotide kinase only 5'-PPP-RNA was capped by guanylyltransferase.
D000255:Adenosine Triphosphate / Q000378:metabolism; D003838:Deoxyadenine Nucleotides / Q000378:metabolism; D006160:Guanosine Triphosphate; D008274:Magnesium / Q000378:metabolism; D009713:Nucleotidyltransferases / Q000378:metabolism; D010766:Phosphorylation; D010770:Phosphotransferases / Q000378:metabolism*; D017856:Phosphotransferases (Phosphate Group Acceptor); D011131:Polyribonucleotides; D012313:RNA / Q000378:metabolism*; D013379:Substrate Specificity; D014616:Vaccinia virus / Q000201:enzymology
D003838:Deoxyadenine Nucleotides; D011131:Polyribonucleotides; D012313:RNA; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D010770:Phosphotransferases; C022347:5'-phosphate-polyribonucleotide kinase; D017856:Phosphotransferases (Phosphate Group Acceptor); D009713:Nucleotidyltransferases; C020842:guanylyltransferase; D008274:Magnesium