Antiviral Res . Characterization of Heparin and Severe Acute Respiratory Syndrome-Related Coronavirus 2 (SARS-CoV-2) Spike Glycoprotein Binding Interactions

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Antiviral Res


. 2020 Jul 9;104873.
doi: 10.1016/j.antiviral.2020.104873. Online ahead of print.
Characterization of Heparin and Severe Acute Respiratory Syndrome-Related Coronavirus 2 (SARS-CoV-2) Spike Glycoprotein Binding Interactions


So Young Kim ¹ , Weihua Jin ² , Amika Sood ³ , David W Montgomery ⁴ , Oliver C Grant ⁴ , Mark M Fuster ⁵ , Li Fu ² , Jonathan S Dordick ⁶ , Robert J Woods ⁴ , Fuming Zhang ⁷ , Robert J Linhardt ⁸



Affiliations

• PMID: 32653452
• DOI: 10.1016/j.antiviral.2020.104873

Abstract

Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) has resulted in a pandemic and continues to spread around the globe at an unprecedented rate. To date, no effective therapeutic is available to fight its associated disease, COVID-19. Our discovery of a novel insertion of glycosaminoglycan (GAG)-binding motif at S1/S2 proteolytic cleavage site (681-686 (PRRARS)) and two other GAG-binding-like motifs within SARS-CoV-2 spike glycoprotein (SGP) led us to hypothesize that host cell surface GAGs may interact SARS-CoV-2 SGPs to facilitate host cell entry. Using a surface plasmon resonance direct binding assay, we found that both monomeric and trimeric SARS-CoV-2 spike bind more tightly to immobilized heparin (K_D = 40 pM and 73 pM, respectively) than the SARS-CoV and MERS-CoV SGPs (500 nM and 1 nM, respectively). In competitive binding studies, the IC₅₀ of heparin, tri-sulfated non-anticoagulant heparan sulfate, and non-anticoagulant low molecular weight heparin against SARS-CoV-2 SGP binding to immobilized heparin were 0.056 μM, 0.12 μM, and 26.4 μM, respectively. Finally, unbiased computational ligand docking indicates that heparan sulfate interacts with the GAG-binding motif at the S1/S2 site on each monomer interface in the trimeric SARS-CoV-2 SGP, and at another site (453-459 (YRLFRKS)) when the receptor-binding domain is in an open conformation. The current study serves a foundation to further investigate biological roles of GAGs in SARS-CoV-2 pathogenesis. Furthermore, our findings may provide additional basis for further heparin-based interventions for COVID-19 patients exhibiting thrombotic complications.

Keywords: COVID-19; SARS-CoV-2; binding interactions; glycosaminoglycans; heparin; spike glycoprotein.