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26 Cards in this Set
- Front
- Back
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structural properties of alpha keratin
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two coiled alpha helices, whose amino acid sequences are a repeating heptamer; amino acids a and d associate w/ one another and are hydrophobic
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blistering that occurs above the basement membrane, due to missense mutations in either KRT5 or KRT14
the mutations result in defective keratin filaments |
epidermolysis bullosa (EB) simplex
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blistering at suprabasal cells, caused by missense mutations in either KRT1 or KRT10
mutation result in defective keratin filaments |
epidermolytic hyperkeratosis
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vitamin A form that is involved in the synthesis of glycoproteins
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retinyl
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basic structure of the dermal matrix
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fibrous protein network embedded in a polysaccharide gel
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properties of the polysaccharide gel structure of the dermal matrix
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hydrated
polyanionic molecular sieve resists compression |
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general structure of hyaluronan and other GAGs
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repeating disaccharide
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core protein w/ one or more covalently attached GAG chains
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proteoglycan
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types of collagen that are fibril-forming (fibrillar)
types that are fibril-associated types that are network-forming |
Type I (90%), II, III, V, XI
Types IX, XII Types IV, VII |
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types of collagen that are found abundantly in the dermis of skin (2)
type of collagen that is found exclusively in the basement membrane |
Types I and III
Type IV |
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general structure of fibril-forming collagens
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triple helix
each chain consists of a repeating triplet every third amino acid is glycine |
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amino acid that disrupts an alpha helical structure
this amino acid is abundant in collagen, partially accounting for it's triple helical structure what in the amino acid's structure is responsible for the inability to form the alpha helix? what is the other structural aspect that contributes to the formation of the collagen helix? |
proline
no amide hydrogen for H-bonding glycine as every third amino acid |
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general mechanism for the synthesis of a collagen fiber
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synthesis of pro-alpha chain
transfer into ER/golgi compartment hydroxylation of prolyl and lysyl residues (hydroxylases) lysyl residues are modified by lysyl oxidase to produce allysine cleavage of propeptides to form tropocollagen self-assembly and aggregation to form collagen fiber |
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condition brought on by ineffective prolyl hydroxylase
what co-factor is missing? |
scurvy
ascorbic acid |
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what condition is brought about by defective lysyl hydroxylase?
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Ehlers-Danlos VI
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what condition is brought about by defective lysyl oxidase?
how does this affect the collagen fibers? |
Ehlers-Danlos V
impaired ability of strands to crosslink |
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linkages found in elastin
4 lysine residues are brought together |
desmosine linkages
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two structural proteins in the dermal layer
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collagen and elastin
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adhesive proteins in the dermal layer (2)
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fibronectin and laminin
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amino acid sequence of fibronectin and laminin that has capacity to bind to cells (integrins)
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arginine-glycine-aspartic acid (RGD) sequence
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two major components of the basal lamina
which one is structural? which one is adhesive? |
collagen and laminin
collagen is structural laminin is adhesive |
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condition involving a collagen type I defect
causes weak bones and skin how many genes are potentially involved? |
osteogenesis imperfecta
either of 2 genes |
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condition that results from a defect in type I collagen
results in easy bruising and hyperextensibility |
Ehler's-Danlos VII
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condition that results from a defect in type III collagen
results in fragile skin and blood vessels |
Ehler's-Danlos IV
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condition that results from a defect in lysyl oxidase
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Ehler's-Danlos V
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condition that results from lysyl hydroxylase defects
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Ehler's-Danlos VI
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