Collagen

Question 1

What is collagen?

Answer 1

major insoluble fibrous protein in extracell. matrix and connective tissue

Question 2

What is the most plentiful protein?

Answer 2

collagen

Question 3

What are examples of fibrous proteins?

Answer 3

collagen and keratin

Question 4

The triple helical structure is held together by what bonds?

Answer 4

hydrogen

Question 5

Collagen is rich in what structure?

Answer 5

secondary structure

Question 6

What types are considered fibrillar collagen?

Answer 6

types 1, 2, 3, 5

Question 7

What types are considered fibril-associated collagen?

Answer 7

types 6 and 9

Question 8

What types are considered sheet-forming collagen?

Answer 8

4

Question 9

What are the 3 amino acids that make collagen?

Answer 9

• glycine
• hydroxyproline
• proline

Question 10

What is the basic structural unit of collagen?

Answer 10

triple helix

Question 11

What is the repeating tripeptide sequence in collagen?

Answer 11

Gly-X-Pro or Gly-X-HPro

Question 12

Does collagen have a right or left-handed twist?

Answer 12

right

Question 13

What number position does glycine appear?

Answer 13

every 3rd position

Question 14

Cross-links provide what for collagen?

Answer 14

more stability

Question 15

Hydroxyproline is important for what?

Answer 15

stabilization in collagen triple helix

Question 16

What 3 things are needed for hydroxylaation?

Answer 16

• prolyl hydroxylase
• ascorbate
• O2

Question 17

Hydroxylysine is important for what?

Answer 17

glycosylation of collagen

Question 18

What is the biosynthesis of type 1 collagen?

Answer 18

1. synthesis of pro-alpha chain
2. hydroxylation of prolines and lysines
3. glycosylation of hydroxylysines
4. self-assembly of 3 pro-alpha chains
5. cystine makes disulfide bonds
6. procollagen triple-helix forms; disulfide bonds disappear
7. secreted out ER and golgi
8. propeptides are cleaved
9. fibril self-assembly; collagen is formed

Question 19

What enzyme allows for cross-linking?

Answer 19

lysyl amino oxidase

Question 20

During the biosynthesis of type 1 collagen, in what order of terminals does the synthesis of the pro-alpha occur?

Answer 20

N -> C

Question 21

During the biosynthesis of type 1 collagen, in what order of terminals does the trple helix formation occur?

Answer 21

C -> N

Question 22

Is post-translational modification intracelluar or extracellular in the biosynthesis of collagen?

Answer 22

intracellular

Question 23

Where are type 1 collgens found?

Answer 23

in skin, cornea, and bone

Question 24

In cartilage, what 2 types of collagen bind together?

Answer 24

type 2 and 9

Question 25

Where is type 4 collagen found?

Answer 25

in the basal lamina

Question 26

What are the 3 diseases caused by abnormal collagen synthesis?

Answer 26

• osteogenesis imperfecta
• Ehlers Danlos syndrome
• scurvy

Question 27

What is osteogenesis imperfecta?

Answer 27

• mutation in type 1 collagen alpha chain
• brittle bones
• mild severe forms
• autosomal dominant

Question 28

What is Ehlers Danlos syndrome?

Answer 28

• joint hypermobility
• easily bruised
• stretchy skin
• variable inheritance

Question 29

What is scurvy?

Answer 29

• due to lack of hydroxylation of Lys and Pro in collagen
• liver spots
• spongy gums, tooth loss
• fingernails decay

Question 30

What is an exmple of a bacterial collagenase?

Answer 30

clostridium histo. -> causes gas gangrene