Collagen Disorders Flashcards
Collagen Structure
3 left handed helices wound into one triple helix
-gly-X-Y with glycine in the middle
Why are glycine mutations really bad in collagen
because they cause the helix to unravel. Glycine can’t be in the middle and it needs to be
Why are 3’ end (carboxy) mutations bad
because the 3’ end is where the collagen winds up from so if there is a mutation there, it prevents the wind up from occurring properly
Type I collagen structure
heterodimer: 2 alpha-1 chains, 1 alpha-2 chain
Type I collagen locations
bones and connective tissue: skin, tendons, sclera
COL1A1 and COL1A2 mutations lead to what? what collagen type do they code for
code for type 1
-leads to osteogenesis imperfecta
Osteogenesis Imperfecta Type 1
- least severe type
- type 1 collagen is normal but there is a decreased amount of it
Osteogenesis Imperfecta Type 2
- more severe than type 1
- type 1 collagen is diminished and structurally abnormal
- frequently lethal at or shortly after birth
Osteogenesis treatment
Can basically only prevent/control symptoms, max mobility, develop bone and muscle strength
Type II collagen structure
homotrimer of 3 alpha-1 chains (chromosome 12)
Type II collagen location
Cartilage: hyaline and elastic cartilage, vertebral discs, vitreous humor of the eye
Interactions of collagen II
- Interacts with proteoglycans, intern, and decor molecules to resist swelling pressure of proteoglycans
- forms thin fibrils in a loose mesh with type IX and type XI collagens in cartilage
Stickler syndrome (what collagen is it associate with, what is it)
collagen II; hereditary arthro-ophthalmopathy
Type III collagen structure
three alpha I chains (COL3A1 on chromosome 2)
- thin collagen fibrils created that form a loosely woven meshwork of reticular fibers
- associates with type I and V collagens to form mixed population fibers in skin
Type III collagen location
skin, blood vessels, hollow organs (within smooth muscle laters of the GI tract and uterus)
