Question

Indicate whether each of the following descriptions better applies to N-linked (N) or O-linked (O) glycosylation. Your answer would be a four-letter string composed of letters N and O only, e.g. OONO.

1 It is abundant in proteoglycans.
2 It involves the attachment of a preassembled block of oligosaccharide onto a protein.
3 It is attached to a serine or threonine residue in the protein.
4 It involves heavily sulfated sugars.

Answer 1

The correct sequence of letters representing whether the descriptions apply to N-linked or O-linked glycosylation is ONOO. N-linked glycosylation involves preassembled oligosaccharides, while O-linked glycosylation is typical for proteoglycans, serine or threonine attachments, and features heavily sulfated sugars.The correct answer is all the above.

Step-by-step explanation:

Indicate whether each of the following descriptions better applies to N-linked (N) or O-linked (O) glycosylation:

1. O - It is abundant in proteoglycans.
2. N - It involves the attachment of a preassembled block of oligosaccharide onto a protein.
3. O - It is attached to a serine or threonine residue in the protein.
4. O - It involves heavily sulfated sugars.

Glycosylation refers to the process where a carbohydrate is covalently attached to a target protein or lipid molecule. N-linked glycosylation occurs when the carbohydrate is attached to the nitrogen atom (amide nitrogen) on the asparagine side chain of a protein. Conversely, O-linked glycosylation occurs when the carbohydrate is attached to the oxygen atom of the hydroxyl group on serine or threonine.

Proteoglycans are proteins heavily modified with carbohydrates, specifically polysaccharide chains called glycosaminoglycans (GAGs), and they typically involve O-linked glycosylation. N-linked glycosylation characteristically involves the attachment of a preassembled block of oligosaccharide, which begins its synthesis in the rough endoplasmic reticulum. Heavily sulfated sugars are more commonly associated with O-linked glycosylation in the structure of proteoglycans.