Identification of two histidines necessary for reovirus mRNA guanylyltransferase activity

Tao Qiu, Cindy L. Luongo

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Grass carp reovirus, a segmented double-stranded RNA virus, is a member of the genus aquareovirus in the Reoviridae family. Grass carp reovirus VP1 was shown to be an mRNA guanylyltransferase. The enzyme demonstrated maximum activity ≤ pH 6.0. This low pH maximum is conserved among the known guanylyltransferases of the Reoviridae family, but is not a property of the KxDG guanylyltransferases. The positive effect of low pH was detected for both autoguanylylation and GMP transfer, the two steps in the guanylyltransferase reaction. The effect of pH on enzymatic activity suggested that histidine protonation is responsible for the observed increase in guanylyltransferase activity. Mutagenesis of the two histidines conserved among the orthoreovirus and aquareovirus guanylyltransferases demonstrated that they are necessary for activity.

Original languageEnglish (US)
Pages (from-to)313-324
Number of pages12
Issue number2
StatePublished - Nov 25 2003
Externally publishedYes


  • Aquareovirus
  • Guanylyltransferase
  • Histidine protonation
  • Mammalian reovirus
  • Orbivirus
  • Reoviridae
  • Reovirus
  • Rotavirus
  • Vaccinia virus
  • mRNA capping

ASJC Scopus subject areas

  • Virology


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