Collagen Fibers

As it is well-known, collagen fibers are naturally occurring proteins found exclusively in animals and they are the main proteins in the connective tissues. Collagen fiber is the most commonly found protein in mammals and it makes up 25 to 35% of the whole body protein. Since 1930s scientists have been performing active research on the conformation of the collagen monomer which is sheet like or microfibrillar. This monomeric structure of the collagen fibers was described by Fraser, Miller and Wess with close observation. The collagen molecule is also called the 'tropocollagen' and is a aggregate of larger collagen fibrils. Given below is a detailed description about collagen fibers and their function.

Collagen Fiber Information

Tropocollagen, is approximately 300 nm in length and 1.5 nm in diameter. It is made up of polypeptide strands known as the alpha chains and each of them is a left-handed helix in conformation. There are three such left-handed helices which are twisted together to form a right-handed triple helix or super helix which are bonded to each other with hydrogen bonds. This entire molecule which is collectively called the collagen fiber is made up of a regular arrangement of amino acids and hence it's called a protein. Read on for information about the formation, types and function of these collagen fibers. More on collagen injections.

Collagen Fiber Types

Collagen is found in many parts of the body but the most common is the collagen fibers connective tissue. Throughout the body there are 29 types of collagen which have been identified till date. However more than 80% of the collagen in the body are of the types I, II, III and IV, each type found in different parts of the body.

• Collagen I is found in the skin, organs, bones and tendons.
• Collagen II is found in cartilages all over the body.
• Collagen III is a major component of reticular fibers and along type I.
• Collagen IV is found in the cell basement membrane.

The most commonly found collagen type is the first one and so we have discussed the formation of the collagen type I for you to get a better idea on how it is formed.

Collagen Fiber Formation

The formation of collagen fibers is mostly in vivo (inside the cell) but you can make it in vitro (outside the cell). More on collagen vascular disease.

In Vivo

• The three peptide chains are formed in the ribosomes along the rough endoplasmic reticulum (RER) and these peptide chains have one registration peptide on one end and a signal peptide on the other end.
• These peptide chains are sent to the lumen of the RER where the signal peptides cleave and these chains are called procollagen.
• Then occurs the hydroxylation of the amino acids like lysine and proline which depends on ascorbic acid as a cofactor.
• Then glycosylation of these hydroxylated amino acid takes place and the triple helical structure of the collagen monomer is formed inside the RER.
• This procollagen is then moved to the golgi apparatus where it is packed to make the collagen fibers and secreted by exocytosis.

In Vitro

• When collagen fibers are formed outside the cell or in the lab, the registration peptides are cleaved and the tropocollagen is formed by the procollagen peptidase.
• These multiple molecules of the tropocollagen together form the collagen fibers by covalent cross linking of the lysine residues.
• These collagen fibers are attached to the cell membranes through fibronectin and integrin proteins.

Collagen Fiber Functions

As collagen fibers are found in the connective tissues and extracellular matrix of the cells, their main function is to support all the tissues around the cell and give the cells a structure from the outside. Since it has excellent tensile strength, it is the main component of cartilages, tendons, ligaments and the skin. It also strengthens the blood vessels and develops many tissues in our body. Such are the functions and uses of collagen fibers. More on collagen supplements.

Collagen fibers being the most important protein for our body physics, is also the roots for our existence. I hope this article helped you in finding out the necessary information about collagen fibers.