8S0M image
Entry Detail
PDB ID:
8S0M
Title:
Crystal structure of the HKU1 receptor binding domain in complex with TMPRSS2 and the nanobody A01
Biological Source:
PDB Version:
Deposition Date:
2024-02-14
Release Date:
2024-06-26
Method Details:
Experimental Method:
Resolution:
3.55 Å
R-Value Free:
0.22
R-Value Work:
0.19
R-Value Observed:
0.19
Space Group:
P 61
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Spike protein S1
Chain IDs:D (auth: A), E (auth: D)
Chain Length:366
Number of Molecules:2
Biological Source:Human coronavirus HKU1 (isolate N5)
Polymer Type:polypeptide(L)
Description:Transmembrane protease serine 2
Chain IDs:A (auth: B), B (auth: E)
Chain Length:395
Number of Molecules:2
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Nanobody A01
Chain IDs:C (auth: U), F (auth: V)
Chain Length:136
Number of Molecules:2
Biological Source:Vicugna pacos
Primary Citation

Abstact

The human seasonal coronavirus HKU1-CoV, which causes common colds worldwide, relies on the sequential binding to surface glycans and transmembrane serine protease 2 (TMPRSS2) for entry into target cells. TMPRSS2 is synthesized as a zymogen that undergoes autolytic activation to process its substrates. Several respiratory viruses, in particular coronaviruses, use TMPRSS2 for proteolytic priming of their surface spike protein to drive membrane fusion upon receptor binding. We describe the crystal structure of the HKU1-CoV receptor binding domain in complex with TMPRSS2, showing that it recognizes residues lining the catalytic groove. Combined mutagenesis of interface residues and comparison across species highlight positions 417 and 469 as determinants of HKU1-CoV host tropism. The structure of a receptor-blocking nanobody in complex with zymogen or activated TMPRSS2 further provides the structural basis of TMPRSS2 activating conformational change, which alters loops recognized by HKU1-CoV and dramatically increases binding affinity.

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