Cells have oligosaccharides displayed on their cell surface that are important for cell-cell recognition.Your friend discovered a transmembrane glycoprotein, GP1, on a pathogenic yeast cell that is recognized by human immune cells.He decides to purify large amounts of GP1 by expressing it in bacteria.To his purified protein he then adds a branched 14-sugar oligosaccharide to the asparagine of the only Asn-X-Ser sequence found on GP1 (Figure 15-32).Unfortunately, immune cells do not seem to recognize this synthesized glycoprotein.Which of the following statements is a likely explanation for this problem? Figure 15-32

Question

Cells have oligosaccharides displayed on their cell surface that are important for cell-cell recognition.Your friend discovered a transmembrane glycoprotein, GP1, on a pathogenic yeast cell that is recognized by human immune cells.He decides to purify large amounts of GP1 by expressing it in bacteria.To his purified protein he then adds a branched 14-sugar oligosaccharide to the asparagine of the only Asn-X-Ser sequence found on GP1 (Figure 15-32).Unfortunately, immune cells do not seem to recognize this synthesized glycoprotein.Which of the following statements is a likely explanation for this problem?  Figure 15-32

Quizplus · Accepted Answer

Oligosaccharides on cell surfaces undergo complex modification processes that involve trimming, addition, and rearrangement of sugars. The synthesized oligosaccharide may need further modification before it becomes mature and able to be recognized by immune cells. Adding the oligosaccharide one sugar at a time or adding it to the serine instead of the asparagine would not necessarily solve the recognition problem. The addition of a disulfide bond may improve the stability of the protein, but it is not directly related to the recognition by immune cells.

Cells Have Oligosaccharides Displayed on Their Cell Surface That Are