7/27/2019 Biochemistry I - Fibrous Prote

1/2

16. what degrades collagen? matrixmetalloproteinases andcollagenases

17. what happens to collagen in theECM?

-cleaved by N and Cprocollagen --peptidases-collagen fibrils areformed-cross-linked via lysyloxidase

18. what happens to the nascentpre-pro-alpha chains in theER?

prolines and lysines arehydroxylated

19. what happens when there is a vitamin C deficiency?

scurvy

20. what is a feature of alpha 1antitrypsin deficiency caused

by mutation?

cirrhosis of liverhomosygotes:pulmonary emphysema

21. what is alpha 1 antitrypsin? a plasma protein thatinhibits neutrophilelastase in alvoeli

22. what is elastin? connective tissue proteinthe gives elasticity,recoil, and strength

23. what is Marfan syndrome? an autosomal dominantconnective tissuedisorder

24. what is osteogenesisimperfecta due to?

mutation in structuralalpha 1 or alpha 2chains in type 1 collagen

25. what is procollagen? 3 pro-alpha cha inshelically wrapped andheld together by H-

bonds

26. what is the AA sequence of collagen alpha helix chains?

Gly-X-Y X = proline

Y = hydroxyproline orhydroxylysine

27. what is the composition of collagen?

3 alpha helix chains in aright ha nded superhelix

28. what is the difference incomposition between elastinand collagen?

elastin is notglycosylated and has nohydroxylysine

29. what is the most clinically important mutation regardingEhler Danlos syndrome?

mutation for collagentype 3 mutation:

blood vessel

30. what is the most commonmutation that causes alpha 1antitrypsin deficiency?

GAG turns into AAG(glu--> lys)

1. biosynthesis of elastin -soluble tropoelastinsecreted in ECM-assemble on cell-surface infoldings viaglycoprotein fibrillin-tropoelastin

molecules becomecross-linkes

2. function of glycine in collagen fits in the center

3. function of proline in collagen ring structurestabilizerrigidity

4. how are tropoelastin moleculescross-linked?

cross-linkes betweenlysines via lysyloxidase:

AKA desmosine link

5. how is progollagen secreted to

ECM?

translocated to Golgi

packaged into vesiclessecreted out of the cell

6. how is the assembly of formingthe superhelix started?

formation of disulfide bonds at the C-terminal of pro-alphachains

7. is each alpha chain in collagen leftor right handed

left

8. what AAs is elastin rich in? proline and glycine

9. what are clinical features of Ehlers Danlos syndrome?

hyper extensible skinhyper mobile jointsocular fragility

10. what are clinical features of Marfan syndrome?

tall s tatureectopia lentismitral valve prolapseaortic root dilationaortic dissection

11. what are clinical features of osteogenesis imperfecta?

brittle bones, bluesclera, hearing loss,dental deformity

12. what are the two main types of fibrous proteins that areimportant?

collagen and elastin

13. what causes Ehlers Danlossyndrome?

mutations in genesfor fibrillar collaf=genmetabolism for types 13 or 4

14. what cofactor does Collagen fibrilcross-linking enzyme lysyloxidase require?

copper

15. what cofactors are required forhydroxylation of proline andlysine on pre-pro-alpha chains in

the ER?

O2 and Ascorbic acid(AKA vitamin C)

Biochemistry I - Fibrous ProteinsStudy online at quizlet.com/_ed6aj

7/27/2019 Biochemistry I - Fibrous Prote

2/2

31. what mutation causes Marfan syndrome? mutations in the fibrillin-1 protein:abnormal fibrillin-1 monomers

32. what type of mutations cause osteogenesis imperfecta? missense mutations:glycine substituted by larger AA

33. where are pro-alpha chains polypeptide chains formed? membrane bound ribosomes as pre-pro-alpha chains

34. where is elastin found? lungs walls of large arterieselastic ligaments

35. where is it majorly synthesized? liver, and some by monocytes and macrophages

36. where is type 1 (fibril-forming) collagen found? bones, skin, tendons, cornea, viscera

37. where is type 2 collagen found? cartilage, invertebral discs , vitreous humor of eye

38. where is type 3 collagen found? skin, blood vessels, viscera

39. where is type 4 collagen found? basil lamina

40. where is type 9 (fibril associa ted) collagen found? cartilage

41. where is type collagen cleaved? at 3/4 and 1/4 length fragments