During the biosynthesis and transport of collagen from the endoplasmic reticulum through the Golgi apparatus to the cell surface, collagen fibrils form extracellularly rather than intracellularly. Which of the following does not help to explain why this happens?
a. Type I procollagen synthesized in cells contains nonhelical segments at each end of the polychain that limit their ability to oligomerize into collagen fibrils.
b. Procollagen must be soluble and small enough to fit within the intracellular transport machinery.
c. Type I procollagen cannot form the triple helical oligomers that are the core structure of any collagen oligomer.
d. Type I procollagen contains hydroxylated proline and lysine residues that prevent polypeptide chain oligomerization within the cell.
Ans: c. Type I procollagen cannot form the triple helical oligomers that are the core structure of any collagen oligomer.
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