COLLAGEN CHEMISTRY AND BIOLOGY DEFINITION: A protein with chains containing repetitive Gly- X-Y sequences allowing formation of molecules with triple-helical domains . The triple-helical domains as well as nontriple- helical domains of the molecules interact to form multimolecular aggregates that function primarily as structural elements in extracellular spaces. Collagens are the most abundant protein in mammals (25% of protein mass).
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COLLAGEN CHEMISTRY AND BIOLOGY COLLAGEN CHEMISTRY AND BIOLOGY DEFINITION: A protein with chains containing repetitive Gly-X-Y sequences allowing formation.
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COLLAGEN CHEMISTRY AND BIOLOGY
DEFINITION:
A protein with chains containing repetitive Gly-X-Y sequences allowing formation of molecules with triple-helical domains.
The triple-helical domains as well as nontriple-helical domains of the molecules interact to form multimolecular aggregates that function primarily as structural elements in extracellular spaces.
Collagens are the most abundant protein in mammals (25% of protein mass).
Locations of Collagens (Skin)
Locations of Collagens (Basement Membranes)
LOCATIONS OF COLLAGEN (VASCULAR SYSTEM)
LOCATIONS OF COLLAGENS
BONESTEETHCARTILAGE
LOCATIONS OF COLLAGENS (TEETH)
LOCATIONS OF COLLAGENS (EYE)
Posterior Polymorphous Corneal Dystrophy
One cause is a dominantly acting mutation in a gene encoding for
collagen VIII (COL8A2). Ref: Coupal et al.
Osteogenesis imperfecta
Blue sclerae of an OI victimCaused by genetic mutations in
collagen genes COL1A1, COL1A2
COLLAGEN TYPES27 types with 45genetically distinct
chains:
1.Fiber-forming collagens: the quantitatively predominate collagenschains form several molecular species:
(Types I, II, III, V, and XI) + (XXIV and XXVII)
procollagen to collagen conversionfibers constructed of staggered, side to side,
Since tropocollagens are 300 nm long, there must be 40 nm gaps between adjacent tropocollagens (5 x 68 = 340 nm)
40 nm gaps are called "hole regions" - they contain carbohydrate and are thought to be nucleation sites for bone formation
Collagen Fibers
Collagen – A Triple Helix
Figure 6.17 In the electron microscope, collagen fibers exhibit alternating light and dark bands. The dark bands correspond to the 40-nm gaps between pairs of aligned collagen triple helices.
Every third residue faces the crowded center of the helix - only Gly fits here
Pro and HyP suit the constraints of φ and ψ
Interchain H-bonds involving HyP stabilize helix
Fibrils are further strengthened by intrachain lysine-lysine and interchain hydroxypyridinium crosslinks
Structural basis of the collagen triple helix
The hole regions of collagen fibrils may be the sites of nucleation for bone mineralization
A disaccharide of galactose and glucose is covalently linked to the 5-hydroxyl group of hydroxylysines in collagen by the combined action of galactosyltransferase and glucosyltransferase.
LYSYL HYDROXYLATION
MINERALIZATION
SYNTHESIS – ASSEMBLY OF A COLLAGEN MOLECULE
SPECIFICITY OF CHAIN ASSOCIATION
EXTRACELLLULAR PROCESSING OF COLLAGEN
FIBER ARCHITECTURE
CROSS-LINKS IN A FIBERPHYSICAL STABILITY
FIBROUS COLLAGEN SUMMARY
INDUSTRIAL AND CLINICAL USES OF COLLAGENDenatured collagen (gelatin): FOODS COATINGS CAPSULESNative collagen: SURGICAL DRESSINGS IMPLANTS TISSUE ENGINEERING