An example of a fibrous protein
¨ Found in skin, tendons, cartilage, bones, teeth, walls of blood vessels.
¨ Structural protein in most animals.
¨ Collagen molecule made of 3 polypeptide chains, each in the shape of a helix (not as tightly wound as an a-helix).
¨ Each chain contains 1000 amino acids - every third amino acid is glycine (the smallest amino acid).
¨ 3 helical chains wind around each other to form a three-stranded 'rope'.
¨ 3 strands held together by H bonds.
¨ Very strong - one quarter the tensile strength of mild steel