Type-II collagen

Type-II collagen is the main component of cartilage, a type of connective tissue found in many parts of the body. It is a fibrillar collagen that is primarily located in cartilage, but can also be found in the vitreous humor of the eye.

Structure

Type-II collagen is a triple helix structure, composed of three polypeptide chains, each of which is a left-handed helix. These three chains are wound together to form a right-handed superhelix, a structure that is stabilized by the presence of hydrogen bonds. Each chain is composed of repeating units of the amino acids glycine, proline, and hydroxyproline.

Function

The primary function of type-II collagen is to provide tensile strength and toughness to tissues that require resistance to mechanical forces, such as cartilage. It also plays a role in the development and maintenance of the extracellular matrix, a three-dimensional network of extracellular macromolecules such as collagen, enzymes, and glycoproteins that provide structural and biochemical support to surrounding cells.

Clinical significance

Mutations in the COL2A1 gene, which encodes the type-II collagen protein, can lead to a variety of disorders. These include achondrogenesis, hypochondrogenesis, Kniest dysplasia, and Stickler syndrome. In addition, degradation of type-II collagen is a key event in the progression of osteoarthritis.

See also

• Collagen, type I, alpha 1
• Collagen, type III, alpha 1
• Collagen, type IV, alpha 1