Collagen Flashcards
(52 cards)
T or F: collagen is an integral membrane protein.
False, it is located completely outside of cells
What sequence is common to all types of collagen?
Gly-X-Y sequence
What type of proteins degrade collagen?
Metalloproteinases
What is primary structural element of connective tissue?
Collagen
T or F: collagen undergoes minimal amounts of post translational processing
False, Collagen is highly post translationally processed
Type I collagen
- Form
- Where
Form:
Fibrillar (fiber form)
Where:
Bone, Skin, Tendon, Cornea, Many others
Type II collagen
- Form
- Where
Form:
Fibrillar
Where:
Cartilage, Vitreous of eye
Type III
- Form
- Where
Form:
Skin, Blood vessels, many other
Type IV
- Form
- Where
Form:
Network
Where:
Basal Lamina Sheets
Type V
- Form
- Where
Form:
Fibrillar
Where:
Bone, Skin, Tendon, Cornea, Many others
***Note: this is the same as type I
Type VIII
- Form
- Where
Form:
Network
Where:
Endothelial Lining, cornea
What features are common to all collagen regardless of tissue type?
- structure
- sequence
- Post-Translational Modifications
Structure:
- 3 domains wound around each other into a triple helix
Sequence:
- Each subunit contains a Gly-X-Y repeating sequence
PTMs:
- Hydroxylation of proline and lysine
T or F: a single collagen fibril contains many collagen strands
True
End to end aggregation of small fibrils form longer fibrils that aggregate to form ____________.
Fibers, collagen fibers self assemble from collagen subunits
T or F: different forms of collagen are genetically distinct
True, many different collagen genes encode for different types
What proteins commonly fill the x, y positions in Gly-X-Y.
- Hydroxyproline (HYP, and PRO)
Why is glycine nesessary at every 3rd amino acid in collagen?
- is H for an R group is the only thing small enough to fit in the triple helix
What is the result of changing gly to cys in the collagen sequence Gly-X-Y?
- Resultant disease
- Cysteine has a larger side chain and puts a bulge in the collagen
- This weakens the collagen
- Osteogenesis imperfecta results (aka brittle bone disease)
**Normally this is a small defect but in collagen this glycine is vital
What it is needed for production of hydroxyproline and hydroxylysine needed for collagen formation?
- what does a deficiency result in?
- Vitamin C
- Vitamin C deficiency leads to scurvy
What enzyme is uses vitamin C as a cofactor?
- Prolyl Hydroxylase enzyme
What are the substrates and products of prolyl hydroxylase?
- Coefactors
Substrates:
Proline + alpha KG + O2
Products:
Hydroxyproline + Succinate + CO2
Cofactor:
VITAMIN C
Lysyl Hydroxylase
- Reaction
- Substrates
- Products
- Coefactors
- make hydroxylysine
Substrate:
Lysine
Product:
Hydroxylysine
Cofactor:
Vitamin C
What addition can be made to hydroxylysine?
***this is important
It can be O-glycosylate for collagen specific glycosylation
Slow wound healing and bleeding of gums and lips are symptoms of what disease related to collagen?
- Scurvy, resulting from Vitamin C deficiency
- Scurvy results from lack of Hyroxyproline and Hydroxylysine
