N-linked alpha-2,3-linked sialic acid-containing glycoconjugate (alpha2,3-Sia)

N-linked alpha-2,3-linked sialic acid-containing glycoconjugates are complex carbohydrate structures attached to the amide nitrogen of asparagine residues within proteins. These molecules serve as critical cell-surface receptors, most notably for avian influenza viruses (e.g., H5N1) and certain bacterial pathogens like Streptococcus pneumoniae (Shinya et al., 2006). The specific alpha-2,3 linkage between the terminal sialic acid (N-acetylneuraminic acid) and the penultimate galactose residue is a key determinant of host-pathogen specificity. In humans, these glycoconjugates are primarily localized in the lower respiratory tract, specifically on type II pneumocytes in the alveoli, which explains the severe pneumonia associated with avian flu infections (Nicholls et al., 2007). Therapeutic strategies targeting these glycans often utilize sialidases, such as DAS181, to enzymatically remove the terminal sialic acid, effectively stripping the docking station for viruses and preventing infection (Moss et al., 2012). Beyond infectious disease, altered expression of these sialylated glycans is frequently observed in various cancers, where they contribute to tumor cell migration, metastasis, and immune evasion (Varki, 2017).

Other names

alpha2,3-linked sialic acidsNeu5Ac-alpha2,3-GalAvian influenza virus receptorSA-alpha2,3-Galalpha2,3-sialylated N-glycans

Enzymatic removal of terminal sialic acid residues by host-targeted sialidases (e.g., DAS181) prevents viral hemagglutinin from binding to the host cell, thereby inhibiting viral entry and infection (Moss et al., 2012).