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Updated: Jun 20, 2026
10:40
Analysis of Group IV Viral SSHHPS Using In Vitro and In Silico Methods
Published on: December 21, 2019
Structural basis for ligand and substrate recognition by torovirus hemagglutinin esterases
Martijn A Langereis1, Qinghong Zeng, Gerrit J Gerwig
1Virology Division, Department of Infectious Diseases & Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CH Utrecht, The Netherlands.
Summary
Hemagglutinin esterases (HEs) bind to sialic acids using distinct lectin and esterase domains. Structural analysis reveals key interactions for substrate specificity, offering insights into HE evolution and viral receptor selection.
Area of Science:
- Virology
- Structural Biology
- Glycobiology
Background:
- Hemagglutinin esterases (HEs) are viral glycoproteins crucial for attachment to O-acetylated sialic acids (Sias).
- HEs possess dual functions as lectins and receptor-destroying enzymes, mediated by separate protein domains.
- Understanding HE evolution and Sia specificity is limited.
Purpose of the Study:
- To elucidate the molecular basis of sialic acid specificity in torovirus HEs.
- To investigate the structural and functional interplay between HE esterase and lectin domains.
- To provide insights into the evolutionary mechanisms driving HE diversity.
Main Methods:
- X-ray crystallography of porcine and bovine torovirus HEs complexed with receptor analogs.
- Structure-guided biochemical analysis of esterase domain function.
- Comparative analysis of HE structures and sequences.
Main Results:
- Torovirus HEs form homodimers with conserved sialate-O-acetylesterase domains but unique lectin sites.
- A functionally conserved arginine-Sia carboxylate interaction is critical for Sia binding and positioning in the esterase domain.
- A single-residue difference explains the porcine torovirus HE's preference for 9-O-acetylated Sias over di-O-acetylated forms.
Conclusions:
- HE esterase and lectin domains have coevolved, influencing receptor and substrate specificity.
- The porcine torovirus HE's specific preference for certain Sias may be an adaptation for replication in swine.
- Findings illuminate HE evolution and the mechanisms of viral protein-receptor interactions.
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