Key Difference – Type 1 vs 2 Collagen
Collagen is a fibrous protein found in connective tissues, skin, bone, etc. It provides strength and firmness to various parts of the body. Collagen has a complex structure composed of three polypeptide chains packaged into triple helix configuration. There are different types of collagen proteins found in the body. Among them, type 1, 3 and 2 are abundant. Type 1 collagen is the most abundant collagen in mammals and found in skin, tendons, ligaments, and bones. Type 2 is the most abundant collagen in the cartilage. This is the key difference between type 1 and 2 collagen.
CONTENTS
1. Overview and Key Difference
2. What is Collagen
3. What is Type 1 Collagen
4. What is Type 2 Collagen
5. Side by Side Comparison – Type 1 vs 2 Collagen
6. Summary
What is Collagen?
Collagen is a major structural protein found in the extracellular matrix of the various connective tissues in animals and humans. It is the most abundant protein found in mammals. Collagen exists in the form of long thin fibrils which are very hard and insoluble. It has three polypeptide strands known as alpha chains wind together to give the triple helix configuration to collagen. Each polypeptide chain contains at around 1000 amino acids comprising of glycine, proline and hydroxyproline. Glycine resides in every three amino acids characterizing repetitive Gly-X-Y arrangement of amino acids in the collagen structure. X and Y are mostly occupied by proline and hydroxyproline. Therefore, glycine-proline-hydroxyproline sequences are abundantly found in collagen fibril.
Collagens are encoded by the gene family COL, and there are 45 different collagen-encoding genes in this family. There are approximately sixteen different collagen types. Among them, type 1, 2 and 3 are more abundant. These types vary with the assembly of polypeptide chains, the length of the helix, interruptions in the helix and differences in the terminations of the helixes, etc.
Collagen synthesis is influenced by Vitamin C since it is required for the production of hydroxyproline amino acids in the collagen fibril. Collagen production reduces with aging. It is also affected by the exposure to ultraviolet radiation and some other environmental factors. Some bacteria and viruses are also capable of degrading collagen and interfering with collagen synthesis. Collagen levels are reduced due to smoking, autoimmune disorders, sunlight, high sugar consumption, etc.
Figure 01: Triple helix structure of collagen
What is Type 1 Collagen?
Type 1 collagen is the most common collagen found in the body. It accounts for approx. 90% of the total collagen in the body. It is prevalent in various body parts such as skin, tendon, vascular ligature, organs, bone, etc. It was the first collagen characterized due to its abundance in the extracellular matrix and ease of isolation. It has two alpha1 chains and one alpha2 chain, each having precise 1050 number of amino acids.
Figure 02: Fibrils of collagen type 1
What is Type 2 Collagen?
Type 2 collagen is the main component of the extracellular matrix of the cartilage. It accounts for 50% of the cartilage protein. Type 2 collagen exists in the cartilage matrix crosslinked with the proteoglycans. Collagen 2 is also found in vertebral disks, inner ear and the vitreous. Collagen 2 is composed of three pro alpha1 chains. The COL2A1 gene is encoded for the expression of type 2 collagen in the body. Type 2 collagen synthesis is reduced with age and is taken as oral supplements for joint and cartilage health.
What is the difference between Type 1 and 2 Collagen?
Type 1 vs 2 Collagen |
|
| Type 1 collagens are the most abundant type of collagens. | Type 2 collagens are the third most abundant type of collagen. |
| Location in the Body | |
| They are most abundant in skin, tendon, vascular ligature, organs, and bones. | They are most abundant in cartilages. |
| Fibrils diameter | |
| Fibrils are larger in diameter than type 2 fibrils. | Fibrils are smaller in diameter than those in type 1. |
| Nature | |
| These are packed side by side making thick fibrils. | These are randomly oriented in the proteoglycan matrix of the cartilage. |
| Use as Supplements | |
| They can be mixed with type 3 collagen and make supplements for the skin, muscle and bone | They can be taken as oral supplements for joint and cartilage health. |
| Gene Encoded | |
| COL1A1 | COL2A1 |
Summary – Type 1 vs 2 Collagen
Collagen is the most abundant structural protein found in the mammalian body, accounting for approx. 25% of the total protein. It is an insoluble fibrous protein which gives flexibility and strength to skin, nails, muscles, joints and bones of the body. Collagen exists in 16 different types, and most abundant types are type 1, 2 and 3. Collagen triple helix is composed of three polypeptide chains sequenced with Gly-X-Y amino acids repeats. Type 1 collagen is the most abundant type in the body and found in skin, tendon, vascular ligature, organs, and bone. Type 2 collagen is the major collagen in the cartilage.
Reference:
1. “Structural Proteins: Genes for Collagen.” Encyclopedia of Life Sciences. N.p., n.d. Web. 08 Mar. 2017.
2.”COL1A1 collagen type I alpha 1 chain [Homo sapiens (human)] – Gene – NCBI.” National Center for Biotechnology Information. U.S. National Library of Medicine, n.d. Web. 08 Mar. 2017
3. Lodish, Harvey. “Collagen: The Fibrous Proteins of the Matrix.” Molecular Cell Biology. 4th edition. U.S. National Library of Medicine, 01 Jan. 1970. Web. 08 Mar. 2017
Image Courtesy:
1. “Fibers of Collagen Type I – TEM” By Louisa Howard – (Public Domain) via Commons Wikimedia
2. “Collagentriplehelix” (CC BY-SA 3.0) via Commons Wikimedia