Calcium ions on sialylated N-linked glycans

The target "Calcium ions on sialylated N-linked glycans" refers to a specific molecular motif where divalent calcium ions coordinate with negatively charged sialic acid residues on N-linked carbohydrate chains of glycoproteins. This interaction is a critical structural and functional feature of several biological systems, most notably in the binding of C-type lectins like selectins to their ligands during leukocyte trafficking and inflammation. In the vascular system, P-selectin utilizes a calcium ion in its binding pocket to recognize sialylated and fucosylated glycans, such as Sialyl-Lewis X, on the surface of leukocytes, a process essential for cell rolling and recruitment to sites of injury. Beyond adhesion, these sialic acid-calcium complexes on voltage-gated ion channels modulate channel gating by influencing the local electrostatic environment and cation concentration near the pore. Therapeutically, this interaction is targeted by selectin inhibitors like crizanlizumab to treat vaso-occlusive crises in sickle cell disease, and by sialidases like DAS181 which remove the sialic acid residues to prevent viral entry or modulate neuronal excitability. The target represents a complex biochemical site involving both the glycan structure and the coordinating cation rather than a single protein molecule.

Other names

Sialic acid-calcium complexSelectin ligand binding siteSialyl-Lewis X-calcium motifSialylated N-glycan cation binding siteC-type lectin-sialoglycan interaction site

P-selectin inhibition, Sialic acid cleavage (sialidase activity), Competitive inhibition of glycan binding, Neuraminidase inhibition