Protein oligosaccharide attachment

Other proteins within the organelle catalyze folding of the protein, often attaching cofactors or oligosaccharides and assembling them into active monomers or oligomers. 

The ABO antigens are oligosaccharides attached to membrane proteins or lipids. The H antigen (carried on blood group O cells) is the biochemical... 

Sulfate groups and in some cases fatty acyl groups259 may also be added. Tire exact composition of the oligosaccharides may depend upon the condition of the cell and may be altered in response to external influences.257 Oligosaccharides attached to proteins that remain in the ER membranes may undergo... 

Many proteins synthesized by the ribosomes of the RER contain short chains of carbohydrates (oligosaccharides) and are called glycoproteins. The oligosaccharides are of two main types O-linked (to the OH side chain of Ser or Thr) and N-linked (to the NH2 side chain of Asn). Some proteins are attached to the plasma membrane by a third type of carbohydrate structure called a glycosyl phosphatidylinositol (GPI) anchor. 

O-linked oligosaccharides attached to the protein via O-glycosidic bonds,... 

Just as the phospholipid composition of the membrane is asymmetric, so too is the orientation of transmembrane proteins. Each transmembrane protein has hydrophobic regions that associate with the fatty acid tails of membrane phospholipids. Each also has a imique hydrophilic domain that is always found associated with the outer layer of the membrane and is located on the outside of the cell. This region of the protein t)rpically has oligosaccharides covalently attached. Hence these proteins are glycoproteins. Similarly, each transmembrane protein has a second hydrophilic domain that is always found associated with the inner layer of the membrane and projects into the cytoplasm of the cell. Typically this region of the transmembrane protein is attached to filaments of the cytoplasmic skeleton. 

In contrast to common microarrays, the microsphere system uses optical methods to define the position and structure of a carbohydrate series [25], Incubation of the immobilized microsphere with a fluorophore-labeled carbohydrate-binding protein and the subsequent measuring of the fluorescence signals permits a determination of the binding profile. Binding events take place when one bead emits at both the wavelength of an internal code, which is used as a marker for the oligosaccharide attached to the microsphere, and the fluorophore-labeled protein. 

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