Collagen is a structural protein found in the extracellular matrix of connective tissues throughout the body. It is the most abundant protein in mammals, accounting for 25 to 35 percent of total protein content. It is the main component of connective tissue. Collagen is made up of amino acids bonded together to form a collagen helix, which is a triple helix of elongated fibril. It’s typically present in bones, cartilage, ligaments, tendons and skin. Collagen tissues can be rigid (bone) or compliant (tendon) depending on the degree of mineralization, or they can be a gradient from rigid to compliant (cartilage). Corneas, blood arteries, the stomach, the dentin of teeth and intervertebral discs are all high in collagen. It is a prominent component of the endomysium in muscle tissue. Collagen is found in one to two percent of muscle tissue and makes up 6% of the weight of tendinous, strong muscles. The most frequent cell that produces collagen is the fibroblast. Gelatin is collagen that has been permanently hydrolyzed and is utilised in food and industries. Collagen has a variety of medical applications in the treatment of bone and skin problems.
Structure of Collagen
In vertebrates, there are 28 different forms of collagen, each with at least 46 different polypeptide chains, and many other proteins have collagenous domains. Surprisingly, undamaged collagen was discovered in soft tissue of a 68 million-year-old Tyrannosaurus rex fossil making it the oldest protein ever known. However, that discovery is being questioned. Three parallel polypeptide strands present in a left-handed, polyproline II-type (PPII) helical conformation are wrapped around each other with a one-residue stagger to produce a right-handed triple helix. Because of the tight packing of PPII helices inside the triple helix, every third residue must be Gly, resulting in a repeating XaaYaaGly sequence with any Xaa and Yaa amino acid.
This repetition is found in all forms of collagen, albeit it is interrupted in the triple-helical domain of non fibrillar collagens at specific points. The amino acids (2S)-proline (Pro, 28 percent) and (2S,4R)-4-hydroxyproline (Hyp, 38 percent) are commonly found at the Xaa and Yaa positions of collagen. In collagen, ProHypGly is the most prevalent triplet (10.5 percent). Individual collagen triple helices, referred to as tropocollagen (TC), assemble in a complex, hierarchical manner in animals, resulting in the macroscopic fibres and networks seen in tissue, bone, and basement membranes.
Characteristics of Collagen
Collagen is a long, fibrous structural protein with functions that are distinct from those of globular proteins like enzymes. Collagen fibres are tough bundles of collagen that make up the extracellular matrix, which supports most tissues and provides cell structure from the outside, although collagen is also found inside some cells. Collagen is the major component of cartilage, fascia, tendons, ligaments, bone, and skin, and has a high tensile strength. It is responsible for skin firmness and suppleness, together with elastin and soft keratin, and its breakdown leads to wrinkles that accompany ageing. It helps to build blood vessels and aids in tissue formation. It is found in crystalline form in the lens and cornea of the eye. Given that it appears to fossilise often, even in Mesozoic and Paleozoic bones, it could be one of the most prevalent proteins in the fossil record.
Collagen Supplements
Despite the fact that collagen is abundant in our bodies, it has become a popular supplement for improving hair, skin, and nails—essential components of the fountain of youth. Many people are drawn to the concept of taking a medication that has no side effects and may help them reverse the signs of age.
Collagen was initially introduced as a component of skin lotions and serums. Even doctors questioned its efficacy as a topical therapy because collagen is naturally located in the deeper layers of the skin, not on the surface. Collagen fibres are too large to penetrate the skin’s outer layers, and study has shown little evidence that shorter collagen chains, known as peptides, are more effective.
Oral collagen supplements, including tablets, powders, and certain meals, are thought to be more effectively absorbed by the body, and their popularity has surged among consumers. Hydrolyzed collagen or collagen peptides, which are broken down forms of collagen that are easier to absorb, may be sold. Collagen supplements contain amino acids, which are the building blocks of protein, as well as other nutrients that promote healthy skin and hair, such as vitamin C, biotin, and zinc.
Uses of Collagen
Collagen is used in a wide range of products, from food to medicine. It’s used in burn surgery and cosmetic surgery, for example. In the form of collagen casings for sausages, it is commonly used.
The three tropocollagen strands break partially or entirely into globular domains, possessing a different secondary structure than typical collagen polyproline II (PPII), e.g. random coils, if collagen is subjected to substantial denaturation, e.g. by heating. This is how gelatin is made, which is used in a variety of meals, including flavoured gelatin desserts. Gelatin has been utilised in the cosmetic, pharmaceutical and photography sectors in addition to food. It’s also used as a nutritional supplement. Collagen is generally converted to gelatin, however due to the dry environment, it has survived. Animal glues are thermoplastic, meaning they soften when reheated, and are still employed in the manufacture of beautiful violins and guitars that may need to be reopened for repairs – an application unsuitable with robust, permanent synthetic plastic adhesives. For millennia, animal skins and sinews, especially leather, have been utilized to manufacture useful items.
Conclusion
Collagen can only be found in nature in animals, especially in connective tissues and flesh of mammals. It is basically required for the skin’s suppleness. Ligaments are a special type of connective tissue that generally helps in linking two bones and thereby holds them together. Tendons, which connect muscles to bones, are a similar but usually a distinct type of connective tissue. All of these tissues, including the bones, ligaments, tendons, and skeletal muscles, are made up of proteins. Collagen is the most abundant protein in animals, accounting for around 25% to 35% of total protein content.