You determine the amino acid sequence of a protein and find it contains a long sequence of methionine, followed by a long sequence of proline, followed by a long sequence of valine. Using these data you predict the sequence of this protein's secondary structure will be ________.
A) beta sheets, then a region of no secondary structure, then beta sheets
B) alpha-helices, then a region of no secondary structure, then alpha helices
C) beta sheets, then a region of no secondary structure, then alpha-helices
D) alpha-helices, then a region of no secondary structure, then beta sheets

Question

Quizplus · Accepted Answer

Methionine and valine have a strong tendency to form alpha-helices, while proline has a tendency to disrupt alpha-helices and promote beta-sheet formation. Therefore, the long sequence of methionine and valine suggests the protein may form alpha-helices, while the long sequence of proline suggests a beta-sheet forming region. The pattern observed in the sequence of this protein suggests that it will form alpha-helices, then a region of no secondary structure due to the proline disrupting the helices, followed by beta-sheets formed by the valine residues.

You Determine the Amino Acid Sequence of a Protein and Find