Structure of mouse coronavirus spike protein complexed with receptor reveals mechanism for viral entry.
PLoS Pathog
; 16(3): e1008392, 2020 03.
Article
in English
| MEDLINE | ID: covidwho-5756
ABSTRACT
Coronaviruses recognize a variety of receptors using different domains of their envelope-anchored spike protein. How these diverse receptor recognition patterns affect viral entry is unknown. Mouse hepatitis coronavirus (MHV) is the only known coronavirus that uses the N-terminal domain (NTD) of its spike to recognize a protein receptor, CEACAM1a. Here we determined the cryo-EM structure of MHV spike complexed with mouse CEACAM1a. The trimeric spike contains three receptor-binding S1 heads sitting on top of a trimeric membrane-fusion S2 stalk. Three receptor molecules bind to the sides of the spike trimer, where three NTDs are located. Receptor binding induces structural changes in the spike, weakening the interactions between S1 and S2. Using protease sensitivity and negative-stain EM analyses, we further showed that after protease treatment of the spike, receptor binding facilitated the dissociation of S1 from S2, allowing S2 to transition from pre-fusion to post-fusion conformation. Together these results reveal a new role of receptor binding in MHV entry in addition to its well-characterized role in viral attachment to host cells, receptor binding also induces the conformational change of the spike and hence the fusion of viral and host membranes. Our study provides new mechanistic insight into coronavirus entry and highlights the diverse entry mechanisms used by different viruses.
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Receptors, Virus
/
Carcinoembryonic Antigen
/
Murine hepatitis virus
/
Virus Internalization
/
Spike Glycoprotein, Coronavirus
Type of study:
Experimental Studies
Limits:
Animals
/
Humans
Language:
English
Journal:
PLoS Pathog
Year:
2020
Document Type:
Article
Affiliation country:
Journal.ppat.1008392
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