- See:
Collagen Discussion:
- Discussion:
- type I is the major collagen of tendon and bone, but it is also the predominant in lung, skin, dentin, heart valves,
fascia, scar tissue, cornea, and liver;
- type I collagen is essential for the tensile strength of bone; it is final amount and distribution of these
collagen fibers that will determine the size, shape, and ultimate density of the bone;
- collagen fibers are characterized by an axial periodicity of 640 Ang to approximately 700
depending upon source of collagen;
- presence of high and low protein densities gives it distinctive light and dark bands;
- collagen is unique in that it contains about 1/3 glycine residues;
- it is also rich in hydroxyproline and hydroxylysine residues, contains many alanine residues and very few aromatic amino acids;
- single collagen fibril is made of 3 polypeptides called alpha chains;
- Molecular Defects:
- see
collagen disorders
- molecular defects involving type I procollagen have been identified in several patients & families w/
osteogenesis imperfecta;
-
Marfan's syndrome:
- Marfan syndrome produces long, thin extremities, redundant ligaments & joint capsules, ectopia lentis, & dilatation & rupture of aorta;
- this syndrome may be caused by mutations in genes for type I procollagen or for enzymes that process protein;
