Single-molecule imaging prefusion intermediate conformations of MERS-CoV spike trimers in membrane during entry

Summary: Middle East respiratory syndrome coronavirus (MERS-CoV) entry into host cells is mediated by the spike (S) glycoprotein trimer. The S2 domain of spike promotes membrane fusion for MERS entry, but its mechanism of action is currently elusive. Here, we applied real-time single-molecule fluore...

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Main Authors: Shuvankar Dey, Purba Pahari, Mridul Shukla, Raiees Andrabi, Dibyendu Kumar Das
Format: Article
Language:English
Published: Elsevier 2025-07-01
Series:Cell Reports
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Online Access:http://www.sciencedirect.com/science/article/pii/S2211124725006874
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author Shuvankar Dey
Purba Pahari
Mridul Shukla
Raiees Andrabi
Dibyendu Kumar Das
author_facet Shuvankar Dey
Purba Pahari
Mridul Shukla
Raiees Andrabi
Dibyendu Kumar Das
author_sort Shuvankar Dey
collection DOAJ
description Summary: Middle East respiratory syndrome coronavirus (MERS-CoV) entry into host cells is mediated by the spike (S) glycoprotein trimer. The S2 domain of spike promotes membrane fusion for MERS entry, but its mechanism of action is currently elusive. Here, we applied real-time single-molecule fluorescence resonance energy transfer (smFRET) imaging to MERS-CoV S virions to identify the prefusion intermediate states of the S2 domain on the pathway to membrane fusion and understand their role in S neutralization by S2 stem-helix-targeted neutralizing antibodies. Our observations revealed the S2 domain of unliganded MERS-CoV S to be intrinsically dynamic, with the prefusion conformation transitioning between three distinct prefusion intermediate conformations, whose relative occupancies were remodeled by receptor dipeptidylpeptidase 4 (DPP4), protease TMPRSS2, and antibody binding. Acidic pH dramatically shifts the conformational equilibrium of S2 in favor of the fusion-competent intermediate conformation. Broadly neutralizing antibodies targeting the S2 stem-helix limit the conformational transitions of S2 and inhibit the refolding of spike to the post-fusion state.
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issn 2211-1247
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publisher Elsevier
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spelling doaj-art-167bba4c0e28470d8b5ca4e3a48431ff2025-08-20T02:35:36ZengElsevierCell Reports2211-12472025-07-0144711591610.1016/j.celrep.2025.115916Single-molecule imaging prefusion intermediate conformations of MERS-CoV spike trimers in membrane during entryShuvankar Dey0Purba Pahari1Mridul Shukla2Raiees Andrabi3Dibyendu Kumar Das4Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, IndiaDepartment of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, IndiaDepartment of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, IndiaConsortium for HIV/AIDS Vaccine Development (CHAVD), The Scripps Research Institute, La Jolla, CA 92037, USADepartment of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India; Center for Engineering in Medicine, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India; Corresponding authorSummary: Middle East respiratory syndrome coronavirus (MERS-CoV) entry into host cells is mediated by the spike (S) glycoprotein trimer. The S2 domain of spike promotes membrane fusion for MERS entry, but its mechanism of action is currently elusive. Here, we applied real-time single-molecule fluorescence resonance energy transfer (smFRET) imaging to MERS-CoV S virions to identify the prefusion intermediate states of the S2 domain on the pathway to membrane fusion and understand their role in S neutralization by S2 stem-helix-targeted neutralizing antibodies. Our observations revealed the S2 domain of unliganded MERS-CoV S to be intrinsically dynamic, with the prefusion conformation transitioning between three distinct prefusion intermediate conformations, whose relative occupancies were remodeled by receptor dipeptidylpeptidase 4 (DPP4), protease TMPRSS2, and antibody binding. Acidic pH dramatically shifts the conformational equilibrium of S2 in favor of the fusion-competent intermediate conformation. Broadly neutralizing antibodies targeting the S2 stem-helix limit the conformational transitions of S2 and inhibit the refolding of spike to the post-fusion state.http://www.sciencedirect.com/science/article/pii/S2211124725006874CP: MicrobiologyCP: Molecular biology
spellingShingle Shuvankar Dey
Purba Pahari
Mridul Shukla
Raiees Andrabi
Dibyendu Kumar Das
Single-molecule imaging prefusion intermediate conformations of MERS-CoV spike trimers in membrane during entry
Cell Reports
CP: Microbiology
CP: Molecular biology
title Single-molecule imaging prefusion intermediate conformations of MERS-CoV spike trimers in membrane during entry
title_full Single-molecule imaging prefusion intermediate conformations of MERS-CoV spike trimers in membrane during entry
title_fullStr Single-molecule imaging prefusion intermediate conformations of MERS-CoV spike trimers in membrane during entry
title_full_unstemmed Single-molecule imaging prefusion intermediate conformations of MERS-CoV spike trimers in membrane during entry
title_short Single-molecule imaging prefusion intermediate conformations of MERS-CoV spike trimers in membrane during entry
title_sort single molecule imaging prefusion intermediate conformations of mers cov spike trimers in membrane during entry
topic CP: Microbiology
CP: Molecular biology
url http://www.sciencedirect.com/science/article/pii/S2211124725006874
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