Alpha-2,3-linked sialylated glycan (α2,3-Sia)

Alpha-2,3-linked sialylated glycans are carbohydrate structures found on the terminal ends of glycoproteins and glycolipids on the host cell surface, where a sialic acid residue is attached to a galactose residue via an alpha-2,3-glycosidic bond (PubMed: 16439206). These glycans serve as critical attachment points for various pathogens, most notably avian influenza viruses, which preferentially bind to alpha-2,3-linkages found predominantly in the lower respiratory tract of humans and the intestinal tract of birds (NIH: PMC3180813). In addition to their role in viral entry, these glycans are involved in essential biological processes such as cell-cell recognition, inflammation, and the regulation of protein half-life (UniProt: P04053). In oncology, altered expression of alpha-2,3-sialylated structures, such as Sialyl-Lewis X, is often associated with increased metastatic potential and poor prognosis (PubMed: 22510521). Therapeutic strategies targeting these glycans include the use of sialidases to strip the receptors from the cell surface, thereby blocking viral infection, or the development of small molecule inhibitors that mimic these structures to competitively inhibit pathogen binding (PubMed: 19104077).

Other names

Neu5Ac-alpha-2,3-GalAlpha-2,3-sialic acidAvian influenza virus receptorSialyl-alpha-2,3-galactoseSA-alpha-2,3-Gal

Drugs targeting these glycans typically act by enzymatically removing the sialic acid residues from the cell surface (e.g., sialidases like DAS181) to prevent viral entry, or by inhibiting viral neuraminidase to prevent the release of new virions from the sialylated host cell surface (e.g., Oseltamivir).