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Introduction

Describe the structure of keratin and collagen and show how their structures are suited to their biological functions. Discuss one disease/ metabolic disorder that can arise from a structural defect in either protein. Keratin and collagen are very vital within the body's structure; both are very similar in nature, being that they derive from amino acids, which make up their respective proteins. They both fall under a group of particular proteins known as scleroproteins or fibrous in nature. Majority of their structure consist of left-handed helix structures1. Scleroproteins make up one of the two major protein categories, the other being globular. Keratin and collagen each represent one of the three subclasses within scleroproteins. As scleroproteins their jobs are to provide support and protection for the body. They are adapt for this because of their complex structure of repeating polypeptide chains which strengthen as the bind together; this and their insolubility are vital in maintaining the anatomy of the body. Whilst being similar in some ways, collagen and keratin remain different in their specific functions and role. As mentioned above keratin is one of the three scleroproteins. It is an extremely strong, insoluble tertiary protein; it is the main constituent in the structures of various parts in the body. ...read more.

Middle

High percentages of glycine and alanine aid to the formation of hydrogen bonds between amino and carboxyl groups of adjacent peptide bonds6. The disulphide bridges and hydrogen bonding cause insolubility in things like water. This structural feature is vital in mammals. The long filaments present in the structure provide support for the epithelial cells that contain keratin such as skin. It protects the body from damage by allowing other tissues to form around it and stabilize. Collagen is one of other types of scleroprotein, as with keratin it is an important part in majority of the body's structures. It is the main component in connective tissue. It makes up for roughly 25% of the body's protein7. Its strength and insolubility make it the most abundant protein in mammals. Being a connective protein it is seen in body tissues such as the skin, muscles, tendon and cartilage. There are about 25 different types of collagen that occur in the body. Collagen widely works with the other scleroproteins supporting the body's tissues. It does this by providing support, firmness and strength. Collagen may be seen in different forms such as endomysium and fibrous tissue8, different types being made for different parts of the body such as the cornea, bone, blood vessels as well as the gut. ...read more.

Conclusion

The body's lack of response to the dysfunctional collagen structure allows it to be hydrolyzed. When unstable helices form in the collagen associated with tendons and bones, such as Type I collagen, severely weak bone formation results10. There are 8 types of OI ranging form type I- VIII. The later being the worst case of it. The severity the condition depends on the specific gene defect. OI is typically hard to generalize as it varies from person to person, even when two people in the same family have the same form of it, the characteristics may be completely different. Symptoms of the condition vary; they may include blue sclera and early hearing loss. Milder forms of OI result in bowed arms and legs, scoliosis and kyphosis11. Currently there aren't any cures for the condition. Treatment is directed toward preventing or controlling the symptoms, maximizing independent mobility, and developing optimal bone mass and muscle strength. Various forms of therapy are in place to reduce suffering for individuals with the condition. In extremely severe cases a surgical procedure called rodding is used. This involves inserting metal rods through the length of the long bones to strengthen them and prevent and/or correct deformities12. Research into various medication and other treatments are being explored, some include growth hormones, gene therapy and other multiple types of drugs. ...read more.

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