Biology 2581B Study Guide - Quiz Guide: Osteogenesis Imperfecta, Disulfide, Alpha Helix
3 Jun 2020
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Fibrous and globular proteins make up about half and half the total protein content of the body. Main properties of fibrous proteins: extended protein structure, secondary structure is simple based on one type, quaternary structure is held together by covalent bridges. Occurs in hair, nails, outer layer of skin. Almost the entire dry weight of these materials, made by epidermal cells. The secondary structure is alpha helix it is rich in amino acids that favour alpha-helix formation (phe, These hydrophobic side chains are on the alpha helix surface explaining its insolubility. It"s rich in cys residues which form disulphide bridges between cys in separate alpha helices to connect them. Alpha keratin is constructed from two supercoiled alpha-helices. Disulphide bridges are also frequently used to stabilise the interior of a global protein. It was also found that people who had brittle bone disease had low levels of disulphide bonds.
