Question

"What will probably be the effect on a protein if you replace the amino acid proline with the amino acid glycine (side chain -H) at several points?

A.The altered protein will have shorter helices than before.
B. There will be less rotation around backbone bonds than before.
C. The altered protein will have fewer hydrogen bonds than before.
D. The primary structure of the altered protein will be shorter than before.
E. The altered protein will have longer helices than before."

Answer 1

Replacing proline with glycine in a protein can result in longer alpha helices due to glycine's smaller and less rigid structure, which could alter the protein's overall shape and function.

Step-by-step explanation:

The effect of replacing the amino acid proline with glycine at several points in a protein is significant due to their structural differences. Proline is unique among the amino acids because it has a cyclic structure that locks it into a rigid conformation, which can disrupt or end helical structures in proteins, serving as a structural turning point. On the other hand, glycine, with its small hydrogen as an R group, provides more flexibility to the protein structure.

Replacing proline with glycine may lead to a protein with longer helices, as glycine is less rigid and does not impose the structural constraints that proline does. Consequently, there may be fewer structural disruptions, allowing alpha helices to extend. This change could potentially alter the protein's overall three-dimensional shape and its function, which is critically dependent on its structure.