title: Modification of the 5'-terminus of mRNA by soluble guanylyl and methyl transferases from vaccinia virus.
abstract: RNA guanylyl and methyl transferases have been solubilized from vaccinia virus cores. The guanylyl transferase specifically adds a GMP residue to the 5'-terminus of unmethylated vaccinia virus mRNA to form the structures G(5')ppp(5')Gp- and G(5')ppp(5')Ap-. Studies with [alpha-32P]GTP and [beta, gamma-32P]GTP indicated that only the alpha-phosphate is transferred. In the presence of S-adenosylmethionine, the methyl transferases convert the blocked 5'-termini to m7G(5')ppp(5')Gmp- and m7G(5')ppp(5')Amp-. Similarly, the enzymes can modify synthetic poly(A) to form the structure m7G(5')ppp(5')Amp-.
mesh_terms: D002118:Calcium / Q000494:pharmacology; D002848:Chromatography, DEAE-Cellulose; D004789:Enzyme Activation / Q000187:drug effects; D006150:Guanine Nucleotides; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D008780:Methyltransferases / Q000378:metabolism*; D012316:RNA Nucleotidyltransferases / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism*; D012436:S-Adenosylmethionine / Q000378:metabolism; D014616:Vaccinia virus / Q000201:enzymology*
chemical_list: D006150:Guanine Nucleotides; D012333:RNA, Messenger; D012367:RNA, Viral; D008345:Manganese; D012436:S-Adenosylmethionine; D008780:Methyltransferases; D012316:RNA Nucleotidyltransferases; D008274:Magnesium; D002118:Calcium