Biochemistry 2280A Study Guide - Midterm Guide: Procollagen-Proline Dioxygenase, Osteogenesis Imperfecta, Alpha Helix
30 Apr 2018
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Biochemistry 2280 – Midterm
Protein Function
Understand collagen’s properties
- fibrous protein; forms strong fibres or sheets
- most common protein in animals (about 25-30%)
- connects and strengthens tissues
- family of proteins numbered I to XIV
- rich is glycine; one in every third position (important — any other amino acid pushes the
chain apart)
- also high in proline (and some lysine)
• both hydroxylated:
• hydroxyproline — OH groups form H bonds to help keep triple helix together
• hydroxylysine — OH groups serve as sites of sugar addition; involved in cross-linking
reaction
- gives a thin, long, very strong molecule
- hydrophobic and insoluble
Describe the biochemical synthesis and function of collagen
▪ once hydroxylated, three strands assemble together at the C-terminal and winding
around each other to form a tight rope with frayed ends
• this is pro-collagen (soluble)
▪ hydroxyl groups on hydroxyproline form H-bonds
▪ the glycine allows the chains to be tightly together
▪ polyproline type II helix because too much proline and hydroxyproline to form alpha
helix
• more extended than alpha-helix
List diseases associated with collagen and the etiology of these diseases
Scurvy
• lack of vitamin C (ascorbic acid) in diet
• vitamin C is needed for enzyme that hydroxylates Proline (prolyl hydroxylase)
• non-hydroxylated proline = unstable collagen
Osteogenesis imperfecta bad bone
• often glycine mutations
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Fibrous protein; forms strong fibres or sheets. Most common protein in animals (about 25-30%) Family of proteins numbered i to xiv. Rich is glycine; one in every third position (important any other amino acid pushes the chain apart) Also high in proline (and some lysine: both hydroxylated, hydroxyproline oh groups form h bonds to help keep triple helix together, hydroxylysine oh groups serve as sites of sugar addition; involved in cross-linking reaction. Gives a thin, long, very strong molecule. List diseases associated with collagen and the etiology of these diseases. Scurvy: lack of vitamin c (ascorbic acid) in diet, vitamin c is needed for enzyme that hydroxylates proline (prolyl hydroxylase, non-hydroxylated proline = unstable collagen. Osteogenesis imperfecta (cid:894)(cid:862)bad bone(cid:863)(cid:895: often glycine mutations, prevent proper assembly of triple helix, leads to lack of collagen. Ehlers-danlos syndrome (eds: group of inherited connective tissue disorders, caused by a defect in the synthesis of collagen.
