Biochemistry of the ECM Flashcards
What type of molecule s collagen
A protein
What is the structure of collagen
It has a triple helical structure.
How does a single collagen chain become the triple helix structure
Three single left handed collagen fibres twist together to create a right handed triple helix.
What are the two major amino acids which make up collagen
Glycine and proline
What is the general formula for the amino acid make-up of collagen
(Glyc-X-Y)n - every third amino acid is glycine, the other two tend to be prolines.
What type of proline tends to make up the amino acid chain of collagen alongside glyceine
3-hydroxyproline and 4-hydroxyproline.
Why are glycine and proline the amino acids making up collagen
Because these are small amino acids - there is only space for small amino acids and these allow tight packing.
Why is collagen nutritionally poor
Hydroxyproline is unstable and it is deficient in other amino acids.
What are the three chains that wind together to make a collagen molecule
The three chains can be identical or non-identical.
In which type of collagen are the chains non-identical
Type I
In which types of collagen are the chains identical
Type II, III and IV.
What are the three chains which make up type one collagen
2 alpha 1 chains and 1 alpha 2 chain.
Where is type I collagen found
Bone, tendon, skin, lung, cornea, arteries
Where is type II collagen found
Cartilage.
Where is type III collagen found
Skin, lung, uterus, arteries, ligaments.
Where is type IV collagen found
Basement membranes
Towards which terminal do collagen chains associate
The C terminal
What is required in order for individual collagen chains to wind together into a triple helix
Hydroxylation
What is the process of the formation of a collagen fibril
Individual collagen chains associated at C termini. They then undergo hydroxylation and glycosylation and wind together to form a triple helix. The triple helix is extruded from the cell and the N and C termini are cleaved to form a tropocollagen molecule. Tropocollagen molecules are then cross-linked to form a collagen fibril.
What kind of structure do elastin fibres form (like how collagen fibres form a triple helix)
A mesh
What is the name of the structures which link three or four elastin chains together
Desmosines.
What is the structure of elastin fibres
There is an elastin core surrounded by micro-fibrils.
What is the relationship between elastin fibres and emphysema
Elastin can be degraded by extracellular proteinases released by neutrophils in the inflammatory response. This can lead to emphysema where alveolar walls are broken down.
What is the role of alpha 1 antitrypsin
Alpha 1 antitrypsin has a role in inhibiting the extracellular proteinases released by neutrophils in the inflammatory response to prevent the degradation of elastin.
