Question

As a researcher you are interested in characterizing a newly discovered protein. Based upon previous data you are convinced that the protein is a membrane protein. However, after sequencing the protein you discover that there are not large stretches of hydrophobic residues in the primary sequence. Based on this data which of the following statements is true?

This data conclusively demonstrates that the new protein is not a membrane protein.

This data conclusively demonstrates that the protein can only be a peripheral membrane protein.

This data indicates that if the protein does have a membrane spanning portion it contains a β-barrel or multiple amphipathic helices.

This data indicates that if the protein does have a membrane spanning portion it is a single α-helix.

The amount of information given is not sufficient to make any of the above conclusions.

Answer 1

Answer: Option C is correct.

Explanation:

The hydrophobic stretch need not be present as a continuous stretch in the primary sequence. The protein folds to its native conformation and amino acids that are distantly located can come closer in the 3-D structure.

If the protein is membrane spanning, it contains a β-barrel or multiple amphipathic helices.