M1 L3 Flashcards
collagen
Describe the primary structure of collagen and explain how the structure confers mechanical properties related to the biological functions of collagen
it contains an amino acid sequence where glycine is repeated every 3rd residue, which is why its so flexible
Briefly explain examples of disease resulting from a lack of, or incorrect, collagen function
scurvy is a disease that forms from a lack of vitamin c. the collagen synthesized cannot form fibers correctly. (less hydroxyproline = less H bonding) causes skin lesions, poor wound healing, blood vessel fragility
explain how the levels of structure are related to the function of collagen in animals
dense connective tissue: (cartilage, tendon) stretches very little, combined strength of intra and intermolecular interactions
loose connective tissue: (skin, lungs) stretches to resist force, does not break and returns to original structure
describe the secondary structure and explain how the structure confers mechanical properties related to the biological functions of collagen
the polypeptide is folded into a LEFT handed ‘poly-proline helix’ with 3.3 amino acids/turn. hydrogen bonds occur between different polyproline helices rather than within one helix in contrast to an α-helix
describe the quaternity structure and explain how the structure confers mechanical properties related to the biological functions of collagen
the assembly of 3 polyproline helices into a triple helixes provides the unit of collagen 4th structure called tropocollagen. 3 LEFT handed poly-pro helices twisted in a RIGHT handed orientation. every 3rd Gly is at the central axis with an H side chain that binds water and X & Y axis
what are the modified amino acids?
hydroxyproline that modifies Pro after protein translation
hydroxylysine modifies Lys.
The enzymes that catalyze the hydroxylation of certain Pro and Lys in collagen is Prolyl hydroxylase, require vitamin C (ascorbic acid)
