Download MendeleyOC43 clinical isolate spike proteins have distinct carbohydrate-binding properties.
Hassan, Z., Jin, M., Liu, Y., Li, Z., Wong, A.H.M., Desforges, M., Forman, A., Nitz, M., Gunawardena, T., Moraes, T.J., Narimatsu, M., Wrana, J.L., Yu, H., Chen, X., Rini, J.M.(2026) Nat Commun
- PubMed: 42143065 Search on PubMed
- DOI: https://doi.org/10.1038/s41467-026-73186-x
- Primary Citation Related Structures:
9OVK, 9OVL, 9OVM, 9OVN, 9OVO - PubMed Abstract:
The human coronavirus HCoV-OC43 (OC43) is the most widespread of the four common cold-causing seasonal coronaviruses, and tissue culture-adapted strains of it have been used for ~50 years. Nevertheless, clinical isolates of OC43 differ from tissue culture-adapted OC43 in ways that call into question the value of the latter as a model. Among these are differences in their entry mechanisms and the activities of their hemagglutinin-esterases (HE). We now show that the spike proteins of OC43 clinical isolates differ from that of the tissue culture-adapted reference strain (OC43-Lab) in their carbohydrate-binding properties and ability to bind mucins, decoy receptors cleaved by the HE. We also show that, unlike HCoV-HKU1 (HKU1), they do not bind with high affinity and specificity the 9-O-acetylated α2-8-linked disialic acid moiety implicated in viral entry for OC43-Lab and HKU1. The spike proteins of the OC43 clinical isolates possess two inserts, not found in OC43-Lab, that flank the carbohydrate-binding site. Our structural analysis of a representative clinical isolate shows that insert-2 is a determinant of these specificity differences and that the carbohydrate-binding site undergoes conformational changes on carbohydrate binding. These structural features are shared by HKU1 and suggest common mechanisms for adaptation to the human sialoglycome.
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
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