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Cryo-EM Structures of the SARS-CoV-2 Endoribonuclease Nsp15

Monica C Pillon1, Meredith N Frazier1, Lucas B Dillard2

  • 1Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.

Biorxiv : the Preprint Server for Biology
|August 18, 2020
PubMed

Insights

New research reveals the structure of SARS-CoV-2 Nsp15, a key enzyme in viral RNA processing. Understanding this enzyme

Area of Science:

  • Structural Biology
  • Virology
  • Drug Discovery

Background:

  • Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) necessitates novel therapeutics.
  • Nsp15, a conserved uridine-specific endoribonuclease in coronaviruses, is a potential drug target for inhibiting viral replication.
  • The mechanism of viral RNA recognition and processing by Nsp15 remains poorly understood.

Approach:

  • Utilized cryo-electron microscopy (cryo-EM) to generate reconstructions of SARS-CoV-2 Nsp15.
  • Obtained a 3.36 Å resolution cryo-EM structure of UTP-bound Nsp15.
  • Analyzed apo-states to investigate active site conformational heterogeneity.
  • Employed mass spectrometry to characterize Nsp15 products and elucidate its enzymatic mechanism.

Key Points:

  • The UTP-bound Nsp15 structure reveals critical active site residues involved in uridine recognition and phosphodiester bond catalysis.
  • Cryo-EM data highlights conformational heterogeneity in the Nsp15 active site across different states.
  • Mass spectrometry confirmed the specificity and mechanism of Nsp15's nuclease activity.

Conclusions:

  • These findings provide crucial molecular insights into SARS-CoV-2 Nsp15's RNA processing.
  • The study offers a structural basis for designing Nsp15-targeted therapeutics against SARS-CoV-2.
  • Understanding Nsp15 function is vital for developing new antiviral strategies.

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