Broad Tricyclic Ring Inhibitors Block SARS-CoV-2 Spike Function Required for Viral Entry

Sneha Ratnapriya, Anthony R. Braun, Héctor Cervera benet, Danielle Carlson, Shilei Ding, Carolyn N. Paulson, Neeraj Mishra, Jonathan N. Sachs, Courtney C. Aldrich, Andrés Finzi, Alon Herschhorn

Research output: Contribution to journalArticlepeer-review


The entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into host cells requires binding of the viral spike glycoprotein to the angiotensin-converting enzyme 2 (ACE2) receptor, which triggers subsequent conformational changes to facilitate viral and cellular fusion at the plasma membrane or following endocytosis. Here, we experimentally identified selective and broad inhibitors of SARS-CoV-2 entry that share a tricyclic ring (or similar) structure. The inhibitory effect was restricted to early steps during infection and the entry inhibitors interacted with the receptor binding domain of the SARS-CoV-2 spike but did not significantly interfere with receptor (ACE2) binding. Instead, some of these compounds induced conformational changes or affected spike assembly and blocked SARS-CoV-2 spike cell-cell fusion activity. The broad inhibitors define a highly conserved binding pocket that is present on the spikes of SARS-CoV-1, SARS-CoV-2, and all circulating SARS-CoV-2 variants tested and block SARS-CoV spike activity required for mediating viral entry. These compounds provide new insights into the SARS-CoV-2 spike topography, as well as into critical steps on the entry pathway, and can serve as lead candidates for the development of broad-range entry inhibitors against SARS-CoVs.

Original languageEnglish (US)
Pages (from-to)2045-2058
Number of pages14
JournalACS Infectious Diseases
Issue number10
Early online dateSep 2022
StatePublished - Oct 14 2022

Bibliographical note

Funding Information:
The authors thank the following researchers: Louis Mansky, the University of Minnesota for providing a plasmid for expression of the double mutant (K1269A H1270A) SARS-CoV-2 spike; Jason McLellan, the University of Texas at Austin for providing plasmids for expression of soluble RBD-mFC and NTD-mFC; Stefan Pöhlmann, the University of Göttingen for providing plasmids for the expression of SARS-CoV-1 and SARS-CoV-2 spikes; Fang Li, the University of Minnesota for providing the 293T-ACE2 cells; and Fatemeh Khadir, the University of Minnesota for purifying the RBD-mFC and NTD-mFC. The authors thank the Laboratoire de Santé Publique du Québec for the live SARS-CoV-2 D614G virus and the CRCHUM BSL3 facility. The work was supported by an internal grant from the University of Minnesota Medical School to A.H. ORIP/NIH Shared Instrument Grant 1S10OD021539-01 to the ITDD/HTS Lab was used to purchase the Biacore S200 instrument. A.R.B. and J.N.S. were supported by R35 GM131814 and by a Group Grant from the Institute for Engineering in Medicine at the University of Minnesota. Work perfomed in the Finzi Lab was supported by le Ministère de l’Économie et de l’Innovation du Québec (programme de soutien aux organismes de recherche et d’innovation) and a CIHR foundation grant #352417 to A.F. A.F. is the recipient of Canada Research Chair on Retroviral Entry No. RCHS0235 950-232424.

Publisher Copyright:
© 2022 American Chemical Society.


  • SARS-CoV-2
  • entry inhibitors
  • mode of action
  • small molecules
  • spike

PubMed: MeSH publication types

  • Journal Article
  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural


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