Comparative Structural and Functional Analysis of Bunyavirus and Arenavirus Cap-Snatching Endonucleases

The cap-snatching mechanism exists in Segmented negative strand RNA viruses (sNSVs) of the arena-, bunya- and orthomyxovirus for mRNA synthesis. Authors focused on that the location of cap-binding domain was not confirmed in bunya- and arenavirus. To confirm the locations and profile of cap-snatching nuclease, they analyzed three dimensional structures, shift of melting temperature of endonuclease crystal in with/without divalent metal ions, Hantaan (one of Bunyavirus) endonuclease activity rates in comparison with other sNSVs, mutational analysis of endonuclease activity, iron induced stability of Hantaan endonuclease, structural characterization of divalent metal ions binding to Lassa (one of Arenavirales) endonuclease and mutational analysis of endonuclease activity, iron induced stability of Lassa endonuclease. These results showed that there are 2 types of endonucleases in sNSVs. One is for orthomyxovirus and bunyavirus and contains characteristic catalytic histidine. The other is for arenavirus without histidine and shows poorer activity.

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