%0 Journal Article %A Pizarro, José L. %A Sandino, Ana María %A Pizarro, Jacqueline M. %A Fernández, Jorge %A Spencer, Eugenio %T Characterization of rotavirus guanylyltransferase activity associated with polypeptide VP3 %D 1991 %J Journal of General Virology, %V 72 %N 2 %P 325-332 %@ 1465-2099 %R https://doi.org/10.1099/0022-1317-72-2-325 %I Microbiology Society, %X Rotaviruses transcribe mRNA containing a 7mGpppGmp cap at the 5′ end in vitro. Guanylyltransferase activity associated with the viral particle was detected by SDS-PAGE due to the formation of a nucleotide-enzyme complex when the virus was incubated with [α-32P]GTP. Using purified viral particles it was shown that only the core polypeptide VP3 exhibits the ability to form a complex with the nucleotide. The reaction is specific for GTP or dGTP when Mg2+ is used as a cofactor. The reaction also depends on the incubation temperature and the pH, as described for other guanylyltransferases. The GMP-VP3 complex transfers the GMP to pyrophosphate, synthesizing GTP or GDP, resulting in the formation of a GpppG cap. These properties of the complex allowed the core polypeptide VP3 to be identified as the rotavirus guanylyltransferase. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-72-2-325