Fusion glycoprotein (92-106) [Human respiratory syncytial virus],(C73H124N22O25S), a peptide with the sequence H2N-Glu-Leu-Gln-Leu-Leu-Met-Gln-Ser-Thr-Pro-Pro-Thr-Asn-Asn-Arg-OH, MW= 1741.96. Glycoproteins are proteins that contain oligosaccharide chains (glycans) covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. Secreted extracellular proteins are often glycosylated. In proteins that have segments extending extracellularly, the extracellular segments are also glycosylated. Glycoproteins are often important integral membrane proteins, where they play a role in cell–cell interactions. Glycoproteins are also formed in the cytosol, but their functions and the pathways producing these modifications in this compartment are less well understood⁽¹⁾. One example of glycoproteins found in the body is mucins, which are secreted in the mucus of the respiratory and digestive tracts. The sugars attached to mucins give them considerable water-holding capacity and also make them resistant to proteolysis by digestive enzymes.Glycoproteins are important for white blood cell recognition, especially in mammals⁽²⁾. Examples of glycoproteins in the immune system are:molecules such as antibodies (immunoglobulins), which interact directly with antigens. molecules of the major histocompatibility complex (or MHC), which are expressed on the surface of cells and interact with T cells as part of the adaptive immune response.

Figure1  the structures of glycoprotein

Figure 2  Mechanisms of glycoprotein cell receptors

Ref:

1. Ruddock & Molinari (2006) Journal of Cell Science 119, 4373–4380

2. Funakoshi Y, Suzuki T (January 2009). "Glycobiology in the cytosol: The bitter side of a sweet world". Biochim. Biophys. Acta 1790 (2): 81–94.