Collagen is a major structural feature in your body. It primarily consists of re
ID: 43327 • Letter: C
Question
Collagen is a major structural feature in your body. It primarily consists of repeating glycine, proline, and hydroxyl proline triplicates.
a) What R-group does glycine have?
b) Would you consider glycine a small or large amino acid?
c) what role does glycine have in helping maintain the tight collagen triple helix structure?
d) What R-group does proline have? What type of amino acid is proline? What role does proline have in helping maintain the tight collagen triple helix structure?
e) Predict what would happen to the structure of the collagen fiber if glycine was replaced with lysine?
Explanation / Answer
a. The R group in glycine is hydrogen.
b. Glycine is a small amino acid.
c. Glycine helps to maintain the stability of collagen as it allows hydrogen bonding and other linkages within the molecule. Since glycine has an uncharge side chain and a small side chain, it is useful in this way.
d. In proline, the R group exists as a cycle where the three CH2 groups are joined to the CH and NH groups. Proline is actually an imino acid. It does not come under any group. Proline helps to stabilize the structure of collagen. the firm structure of proline helps collagen to form left handed helices easily.
e. Glycine has a nonpolar side chain of hydrogen while lysine has a long side chain of amino residues. This makes the amino acid positively charged. If lysine replaced glycine, the intramolecular hydrogen bonding would not be possible in the structure of collagen. The collagen fiber will not be able to form groups.