These interruptions are useful because they allow proteolytic cleavage of the structure overcoming the resistance to proteases of native triple helices. FACITs collagens have their triple helix interrupted by non-collagenous domains which can act as joints. įACITs (fibril-associated collagens with interrupted triple helices) do not form fibrils by themselves, but they are associated with the surface of collagen fibrils.
PORCINE GELATIN WEIGHT SKIN
Fibrillar collagen is the most abundant collagen in vertebrates and it plays a structural role by contributing to the molecular architecture, shape, and mechanical properties of tissues such as tensile strength in skin and the resistance to traction in ligaments (collagens type I, II, III, V, XI, XXIV, and XXVII). Ĭollagen has been classified into different families such as fibrillar and network-forming collagens, the FACITs (fibril-associated collagens with interrupted triple helices), MACITs (membrane-associated collagens with interrupted triple helices), and MULTIPLEXINs (multiple triple-helix domains and interruptions). Collagens are different according to their α-chain composition, depending on the repeat and length of the Gly–X–Y amino acid repetition, with and without interruptions, also the occupation of the X and Y positions by proline and its hydroxylated form, hydroxyproline, respectively. Collagen type V is one of the principal components of cell surfaces and placenta. Type IV has been reported in the epithelium-secreted layer of the basement membrane and the basal lamina. For collagen type III, the skin, muscle, and blood vessels are the most common sources of this protein. Collagen type II is present in the cartilages.
Nearly 28 types of collagen have been identified, but collagen type I is the most common in skin, bone, teeth, tendon, ligaments, vascular ligature, and organs. The collagen molecule is formed for a triple helical region and two nonhelical regions at either end of the helix structure with ≈300 kDa molecular weight, 280 nm in length, and 1.4 nm in diameter. This collagen structure is very stable because of the intramolecular hydrogen bonds between glycine in adjacent chains.
The super helix represents the basic collagen structure (quaternary structure). The chains are twisted around each other into a triple helix to form a rigid structure (tertiary structure). These chains are coiled into a left-handed helix with three amino acids per turn (secondary structure). Each alpha chain is composed for 1014 amino acids approximately with a molecular weight around 100 kDa. Collagen is the most important protein produced by the human body, it is mainly formed by the amino acid glycine (33%), proline and hydroxyproline (22%) (primary structure) in a triplex helix which is formed by three α chains.
0 kommentar(er)
