BIOCHEM 2EE3 Lecture Notes - Lecture 4: Beta Sheet, Partial Charge, Hydrogen Bond
3 Apr 2018
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Document Summary
Role in nuclei, cytoplasm and surface of cell types. Every third or fourth amino acid is hydrophobic non polar. Hydrophobic strip along surface area along one face of each helical chain. To maximize the contact between hydrophobic surfaces of two alpha- keratin helices, they entwine with a left handed helical twist. Has a small globular region that is attached to the coiled-coil sequence. Alpha-keratin is hardened in some tissue by disulfide cross-links with several levels of fiber structure (has many cysteines) Form the matrix in bone, major portion of tendons, skin, holds animals together. Made up of tropocollagen molecule - a triple helix of three polypeptide chains. Every third residue must by glycine - any other side chain - too bulky to fit in the triple helix to fit in the triple helix. Left handed helice model favoured by presence of proline or hydroxyproline. Gly-x-y where x is often proline and y is proline or hydroxyproline.
