Collagen
Biology: Cambridge International A Level, topic 2.3.6
Collagen
Collagen is an example of a fibrous protein. Roughly 30% of the protein in your body is collagen. It is found in ligaments, tendons, muscle, cartilage, bone, and skin.
Fibrous proteins
- Fibrous proteins are long and narrow.
- Unlike globular proteins, they are insoluble in water.
- The roles of fibrous proteins are to offer structural support to cells.
Collagen
- Individual molecules of collagen are formed by three polypeptide chains wound around each other.
- The chains wind to form a right-handed helix.
- Individual molecules of collagen are cross-linked together to form long collagen fibers.
- Each fibre of collagen contains thousand of individual collagen molecules.
Glycine
- Every third amino acid in collagen is glycine.
- The -R group of glycine is just an H atom.
- This makes glycine amino acids very small.
- This allows collagen molecules to pack closely together, increasing the strength of the collagen fibres.
- This is important for collagen's role in providing structural support.