Consult the β-sheet in Figure 18.2 and (a) name the bonding responsible for the sheet formation and (b) identify the specific atoms responsible for this bonding.

Draw the hexapeptide Asp-Gly-Phe-Leu-Glu-Ala in linear form showing all of the atoms, and show (using dotted lines) the hydrogen bonding that stabilizes this structure if it is part of an α-helix.

Compare and contrast the characteristics of fibrous and globular proteins. Consider biological function, water solubility, amino acid composition, secondary structure, and tertiary structure. Give examples of three fibrous and three globular proteins. (Hint: Make a table.)

Bradykinin, a peptide that helps to regulate blood pressure, has the primary structure Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg.

b. Bradykinin has a very kinked secondary structure. Why?

What is the difference in hydrogen bonding between an α helix and a β−pleated sheet?

What are some differences between each of the following pairs?

b. an ⍺ helix and collagen

Name the stabilizing attractive force found in secondary structures of proteins.

Describe the differences in the shape of an α helix and a β-pleated sheet.