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Consider the Ramachandran plot. a) If you had a peptide sequence whose dihedral

ID: 313671 • Letter: C

Question

Consider the Ramachandran plot.

a) If you had a peptide sequence whose dihedral angels consistently remained in the following ranges (-56°>>-58°) & (-46°>>-48°), what secondary structure would you expect to see?

b) If you had a peptide sequence whose dihedral angels consistently remained in the following ranges (-134°>>-136°) & (138°<<140°), what secondary structure would you expect to see?

c) If you had a peptide sequence whose dihedral angels consistently remained in the following ranges (98°>>100°) & (-59°<<-61°), what secondary structure would you expect to see?

d) What amino acid shows a larger range of possible phi and psi angles than those shown by this plot? Which amino acid shows a smaller range of possible phi and psi angles than those shown by this plot?

180 120 60 60 120 180 180 (degrees) +180

Explanation / Answer

a) Right handed alpha helix is the secondary structure which is expected.

b) Anti parallel beta sheet is the secondary structure which is expected.