Fibrous Proteins

Question 1

Alfa chains held together by…

Answer 1

Hydrogen bonds

Question 2

Type one collagen contains…

Type two collagen contains…

Answer 2

a1(2)a2

a1(3)

Question 3

Which are types are fibrillar collagen?

Answer 3

Type 1, 2 and 3

Question 4

Which are types are network-forming collagen?

Answer 4

Type 4 and 7

Question 5

Which are types are fibril-associated collagen?

Answer 5

Type 9 and 12

Question 6

Collagen is rich in…

Answer 6

Proline and glycine

Question 7

Repeating sequence in collagen is?

Answer 7

Gly-X-Y (x333)
X frequently is proline
Y frequently is hydroxyproline or hydroxylysine

Question 8

Which carbohydrates glucosylate collagen?

Answer 8

Glucose and galactose

Question 9

Collagen fibrils are formed in..

Answer 9

Extra cellular matrix

Question 10

Collagen molecules are formed in ..

Answer 10

Fibroblasts

Question 11

What does the signal sequence?

Answer 11

Facilitates the binding of ribosomes to the RER and direct polypeptides into RER. This sequence is cleaved off and polypeptide becomes pro-a-chain before collagen.

Question 12

Six steps from pro-a-chain to collagen fibril

Answer 12

1. Hydroxylation (lumen of RER)
2. Glycosylation
3. Assembly and secretion (procollagen, RER to Golgi)
4. Extracellular clevage (nc terminal ECM)
5. Formation of collagen fibril (ECM)
6. Cross link formation (covalent)

Question 13

EDS =

Answer 13

Ehlera-Danlos disease

Question 14

What is EDS?

Answer 14

Inheritable defects in the metabolism of fibrillation collagen. Collagen processing enzymes. Vascular disease and stretchy skin.

Question 15

Osteogenesis imperfecta

Answer 15

Twisted back, easily breaking bones and slow healing. Can prevent folding of triple helix

Question 16

Precursor for elastin

Answer 16

Tropoelastin

Question 17

Elastin is rich on ..

Answer 17

Small nonpolar aa, proline and lysine

Question 18

Cause of Marfan syndrome?

Answer 18

Mutations in the fibrillin gene

Question 19

To make elastin from Tropoelastin you need:

Answer 19

Fibrillin (glycoproteins), lysyl oxidase (allysine residues) = desmosine cross link

Question 20

Alfa1- antitrypsin function?

Answer 20

Inhibits a number of proteolytic enzymes that hydrolyze and destroy proteins.

Question 21

Emphysema

Answer 21

Damage of air sac (alveola) walls

Question 22

Collagen structure?

Answer 22

Long rigid of three polypeptides (Alfa chains) in triple-helix

Question 23

Scurvy?

Answer 23

Caused by: Hydroxylation of proline and lysine needs reducing agent vitamins C (ascorbic acid)
Fibers can not be crossed linked
Symptom: bruises