Collagen

Question 1

What is the shape of fibrous proteins?

Answer 1

Long, rod like cylindrical shaped

Question 2

Do fibrous proteins have a high or low solubility in water?

Answer 2

Low

Question 3

What are examples of fibrous proteins?

Answer 3

Collagen, keratin, tropomyosin

Question 4

Keratin relates to what?

Answer 4

Hair/nails

Question 5

Tropomyosin refers to what?

Answer 5

Muscle

Question 6

What is collagen?

Answer 6

Major insoluble fibrous proteins found inside extracellular matrix and connective tissue

Question 6

Collagen is found in all _____ and _____ to provide framework to give tissues its form and strength.

Answer 6

Tissues and organs

Question 7

About how much protein in your body is made up of collagen?

Answer 7

1/4 or 25%

Question 8

How much does your skin produces collagen?

Answer 8

About 74%

Question 9

The structure of alpha-helix is cross-linked by what?

Answer 9

Disulfide bonds

Question 10

What are examples of alpha-helix structures?

Answer 10

Alpha keratin of hair, feathers and nails

Question 11

What are examples of BETA conformation structures?

Answer 11

Silk fibroin

Question 12

What are examples of collagen triple helix structures?

Answer 12

Collagen of tendon, bone matrix

Question 13

What kind of turn is an alpha chain collagen?

Answer 13

Left hand turn

Question 14

What kind of turn is an alpha helix?

Answer 14

Right hand turn

Question 15

What kind of turn is a triple helix?

Answer 15

Right hand turn

Question 16

A triple helix has 3 ____?

Answer 16

Identical chains

Question 17

Glycine is ALWAYS positioned at what position?

Answer 17

3rd

Question 18

How many residues/turns does collagen have?

Answer 18

3

Question 19

How many residues/turns does alpha helix have?

Answer 19

3-6

Question 20

In a cross section of collagen model, how is each strand bonded to other strands?

Answer 20

Hydrogen bonded

Question 21

In a cross section of a collagen model, Glycine must appear at what space?

Answer 21

Every 3rd space

Question 22

Where are pyrrolidone rings located in during cross section of a collagen model?

Answer 22

On the outside

Question 23

What are the steps of Hydroxylation of Pro Residues in Pro Collagen?

Answer 23

Pro residue + Ketoglutarate + O2 –> 4-hydroxyprolylresidue + Succinate + CO2

Question 24

What is the enzyme required for hydroxylation of pro residues in pro collagen?

Answer 24

Prolyl Hydroxylase and ascorbate (vitamin C)

Question 25

What is collagen glycosylation?

Answer 25

Addition of sugar to hydroxylysine

Question 26

What does the addition if sugar to hydroxylysine do?

Answer 26

Stabilizes the triple helix of collagen

Question 27

What are the steps of the Biosynthesis of Type 1 Collagen?

Answer 27

1. Synthesis of pro-alpha collagen 2. Hydroxylation of selected prolines + lysines 3. Glycosylation of selected hydroxylysines 4. Self assembly of 3 pro alpha chains 5. Pro collagen triple helix formation 6. Secretion 7. Cleavage 8. Self assembly into fibril 9. Aggregation of collagen fibrils to form collagen fiber

Question 28

A covalent cross-linked collagen does what?

Answer 28

Strengthens fiber

Question 29

In covalent cross-linked collagen, Lysol oxidase reaction creates ____ to react with a _____ to form a _____.

Answer 29

Aldehyde; lysine; schiff base

Question 30

What does oxidized lysines react with to form crosslinks?

Answer 30

Themselves or hydroxylysine

Question 31

Type I, II, and III are what type of collagen?

Answer 31

Fibrillar (most abundant type)

Question 32

What are Type I collagen representative tissues?

Answer 32

1. skin 2. tendon 3. bone 4. ligaments 5. dentin 6. interstitial tissues

Question 33

What are Type II and Type IX representative tissues?

Answer 33

1. Cartilage | 2. Viterous humor

Question 34

What are type III representative tissues?

Answer 34

1. SKIN 2. MUSCLE 3. BLOOD VESSELS

Question 35

What type of collagen is Type IX?

Answer 35

Fibril associated

Question 36

What type of collagen is type IV?

Answer 36

Sheet forming

Question 37

Type IX has what kind of domain?

Answer 37

Fibrous and globular

Question 38

What are type IV representative tissues?

Answer 38

All basal laminaes

Question 39

What is OSTEOGENESIS IMPERFECTA?

Answer 39

Disease associated with collagen metabolism: 1. Mutation in type 1 collagen and alpha chain 2. Characterized by brittle bones 3. Autosomal dominant (severe)

Question 40

What is Ehlers-Danlos Syndrome?

Answer 40

Disease associated with collagen metabolism: 1. Joint hypermobility 2. Easily bruised 3. Stretchable skin -> elasticity of skin

Question 41

What is Scurvy?

Answer 41

Disease associated with collagen metabolism d/t the lack of hydroxylation of lysine and proline in collagen: 1. "Liver" spots on skin 2. Spongy gums, -> tooth loss 3. Fingernails decay

Question 42

Lysine and proline in collagen is the _____ for hydroxylation of proline (vitamin C)

Answer 42

Ascorbate

Question 43

What are the 2 types of collagenases?

Answer 43

1. Tissue | 2. Bacterial (Clostridium Histolyticum)

Question 44

Tissue collagenase:

Answer 44

Metalloenzymes involved in tissue remodeling or tumor invasion

Question 45

Clostridium histolyticum:

Answer 45

Activity of toxin O involved in development of gas gangre

Question 46

Collagenases also play a role in what?

Answer 46

1. COPD (Chronic Obstructive Pulmonary Disease) | 2. Cancer metastasis

Question 47

Do fibrous proteins or globular proteins contain larger amounts of secondary structure?

Answer 47

Fibrous proteins

Question 48

What type of fibrous protein structure is characterized by tough, insoluble protective structures of varying hardness and flexibility?

Answer 48

Alpha helix

Question 49

What type of fibrous protein is characterized by soft, flexible filaments?

Answer 49

Beta conformation

Question 50

What type of fibrous protein structure is characterized by high tensile strength, without stretch?

Answer 50

Collagen triple helix

Question 51

Does the single strand polypeptide sequence of collagen adopt a left hand or right hand helical structure?

Answer 51

Left hand

Question 52

In the collagen triple helix, what amino acid increases the stability b/c the side chains repel each other and extend/stretch the chain?

Answer 52

Proline

Question 53

What amino acids that are found in collagen are absent in globular proteins?

Answer 53

Hydroxyproline and hydroxylysine

Question 54

What characteristic of collagen structure produces the cross-striations?

Answer 54

A staggered alignment and cross-linking

Question 55

What are the 3 hydroxylated amino acids in collagen?

Answer 55

4-hydroxyproline, 3-hydroxyproline, and 5-hydroxylysine

Question 56

The hydroxylation of proline can't occur in what conditions?

Answer 56

Anaerobic

Question 57

Proline reacts with what other two substrates in the hydroxylation reaction?

Answer 57

Alpha ketoglutarate and Oxygen

Question 58

What are the biproducts made in the hydroxylation of proline?

Answer 58

Succinate and CO2

Question 59

What is the only amino acid that can be glycosylated in collagen?

Answer 59

Hydroxylysine

Question 60

Glycosylation of hydroxylysine involves the addition of what two sugars?

Answer 60

Glucose and galactose

Question 61

What organelle does the assembly of collagen fibers begin in?

Answer 61

ER

Question 62

What sets of the biosynthesis of type I collagen occurs before the collagen can be secreted from the ER?

Answer 62

Procollagen triple helix formation

Question 63

What amino acid is found at the C-term in collagen to initiate wrapping?

Answer 63

Cysteine

Question 64

What enzyme is used to make the aldehydes that react with lysine to forma a Schiff base for cross-linking in collagen?

Answer 64

Lysol amino oxidase

Question 65

Are lysine cross links more prominent in triple helical or non-triple helical regions?

Answer 65

Non-triple helical

Question 66

Type IV collagen and laminin form what which are held together by other proteins?

Answer 66

Scaffolds

Question 67

What is the basic unit involved in Type IV collagen?

Answer 67

Tetramer

Question 68

The severe form of osteogenesis imperfect has what type of inheritance?

Answer 68

Autosomal dominant

Question 69

What are the 3 important amino acids in collagen?

Answer 69

Proline, hydroxyproline, glycine

Question 70

Which of the following is critical for proline hydroxylation?

Answer 70

``` ATP Ascorbate *** Mg2+ Gluthathione CO2 ```

Question 71

Scurvy results from the dietary deficiency of what?

Answer 71

Ascorbic acid