Spontaneous base flipping helps drive Nsp15’s preferences in double stranded RNA substrates
2025

How Nsp15 Cleaves RNA in Coronaviruses

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Author Information

Author(s): Wright Zoe M., Butay Kevin John, Krahn Juno M., Wilson Isha M., Gabel Scott A., DeRose Eugene F., Hissein Israa S., Williams Jason G., Borgnia Mario J., Frazier Meredith N., Mueller Geoffrey A., Stanley Robin E.

Primary Institution: National Institute of Environmental Health Sciences, National Institutes of Health

Hypothesis

Does Nsp15 initiate base flipping or capture spontaneously flipped bases in double-stranded RNA?

Conclusion

Nsp15 cleaves RNA most efficiently at unpaired uridines that are already flipped out of the helix.

Supporting Evidence

  • Nsp15 cleaves unpaired uridines more efficiently than paired ones.
  • Cleavage efficiency is related to the tendency of uridines to spontaneously flip.
  • Structural studies show Nsp15 binds to flipped uridines in RNA.

Takeaway

Nsp15 is a protein that helps coronaviruses hide from the immune system by cutting RNA. It works best when the RNA has certain parts sticking out.

Methodology

The study used nuclease assays, 19F NMR spectroscopy, mass spectrometry, and cryo-EM to analyze Nsp15's cleavage preferences.

Limitations

The study may not account for all possible RNA structures and contexts in vivo.

Statistical Information

P-Value

0.0002

Confidence Interval

95%

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1038/s41467-024-55682-0

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