Sialic acid receptor components

The viral proteins HA and NA are essential for infection the HA of influenza viruses is responsible to bind the virus to cell-surface receptors during the infection sialic acids are the only known components of the receptors necessary to this interaction the virus does not bind or infect neuraminidase-treated cells [7,8], and binding is restored by re-sialation [9] or addition of sialated glycolipid [10,11],... 

The interesting chemistry of sialic acid has been discussed in several reviews [213,214,215]. Sialic acid is an important component of complex oligosaccharides, when it is placed in the terminal position, and often masks the penultimate saccharide sequences. In this position, it interacts with numerous receptors including the influenza virus neuraminidase, and receptors mediating intercellular interactions such as the selectins (members of the C-t) e animal lectin family) and siglecs (or sialoadhesins, members of the immunoglobulin superfamily). The structure of influenza B neuraminidase in complex with sialic acid has been solved by X-ray crystallography at 2.2 A resolution (O Fig. 17) [216]. 

G. are essential components of receptors for virus and plant agglutinins, and of blood group substances The siderophilins and ceruloplasmin are G.Some G. are membrane carrier proteins The carbohydrate portion of gonadotropic hormones is essential to their biological activity in many cases, selective removal of the terminal sialic acid residues inactivates the hormone. The carbohydrate evidently serves as a label for recognition by a receptor. 

Though the role of A-acetylneuraminic acid as a receptor determinant for influenza virus has been known for 40 years, the actual receptor used by this virus to infect cells has not been identified unequivocally. As sialic acid is a frequent sugar on glycoproteins and glycolipids of vertebrate cells, most surface components contain A-acetylneuraminic acid or a derivative of it. All sialylated molecules present on the cell surface are potential receptors for influenza viruses or paramyxoviruses provided they contain sialic acid according to the requirements discussed above (Section 4.1). In the case of erythrocytes, the majority of the surface-bound sialic acid is present on glycophorin. Following isolation from... 

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