SARS-CoV-2 spike protein ganglioside-binding domain (GBD)

The SARS-CoV-2 spike protein ganglioside-binding domain (GBD) is a specialized region located at the tip of the N-terminal domain (NTD) of the S1 subunit, primarily spanning amino acid residues 111 to 158 [2, 6]. This domain features a highly conserved amino acid triad consisting of Gln-134, Phe-135, and Asn-137 (the QFN triad), which facilitates the virus's initial attachment to host cell membranes by binding to the sugar moieties of gangliosides, such as GM1 [1, 3]. These gangliosides are concentrated in lipid rafts, which serve as platforms that recruit the primary ACE2 receptor, thereby positioning the virus for efficient entry and infection [2, 5]. By acting as a co-receptor or attachment factor, the GBD enhances the viral tropism and infectivity of SARS-CoV-2 [7, 8]. In the context of therapeutic intervention, the GBD is a target for drugs intended to block the earliest stages of the viral life cycle. Compounds such as hydroxychloroquine and chloroquine have been shown in molecular simulations and in vitro assays to bind to gangliosides, effectively masking the site from the viral spike protein [2, 11]. Additionally, the antibiotic azithromycin has been proposed to act as a structural mimic of ganglioside sugars, directly binding to the GBD to prevent viral docking [2, 4]. Neutralizing antibodies, such as 4A8, also target the NTD to disrupt these interactions [2]. Because the NTD is a frequent site for mutations in emerging SARS-CoV-2 variants, monitoring the structural integrity of the GBD is critical for maintaining the efficacy of NTD-directed therapeutics [5, 12].

Other names

SARS-CoV-2 spike protein ganglioside-binding tipGanglioside-binding siteGBSS1-NTD ganglioside-binding siteQFN triad siteGalectin-like domain of SARS-CoV-2 spike

Competitive inhibition of viral attachment to host cell gangliosides and lipid rafts