Proteins

Question 1

What is Amyloidosis?

Answer 1

Protein Misfolding, sometimes to form prefibrils, which fail to degrade and accumulate, causing organ dysfunction - it is seen in many chronic diseases

Question 2

How does Amyloidosis appear under light microscopy and polarized light?

Answer 2

Congo Red dye - light microscopy

apple-green birefringence - polarized light

Question 3

Where is serum amyloid A seen?

Answer 3

chronic inflammation

Question 4

AL type of amyloid protein with gamma or kappa light chains is seen in what disease?

Answer 4

Multiple myeloma

Question 5

ATTR amyloid protein is seen where?

Answer 5

familial mutations

Question 6

Abeta amyloid protein is seen in what disease?

Answer 6

Alzheimer’s

Question 7

Abeta2M amyloid protein is seen in what?

Answer 7

chronic hemodiaylsis

Question 8

What Prion protein is normaly found in the brain?

Answer 8

PrPc

Question 9

Does normal prion protein PrPc have any B-sheet?

Answer 9

it has little to none

Question 10

What type of bonds are used for primary structure?

Answer 10

peptide bonds (covalent)

Question 11

What type of bonds are used for secondary structure?

Answer 11

hydrogen bonds

Question 12

How are α-helix and β-sheets formed?

Answer 12

they are formed by hydrogen bonding between atoms of peptide bonds

Question 13

Hydrogen bonds between atoms of peptide bonds are responsible for what structure?

Answer 13

α-helix

Question 14

Hydrogen bonds between the atoms of peptide bonds of opposite chain are responsible for what structure?

Answer 14

β-sheets

Question 15

What are bends and turns generally composed of?

Answer 15

Glycine and Proline

Question 16

What are the two regular secondary structures?

Answer 16

a-helix and b-sheet

Question 17

What are other secondary structures?

Answer 17

loops and coils

Question 18

What do bends, loops, and turns so in secondary structures?

Answer 18

Reverse the direction of the polypeptide chain

Question 19

In which structure(s) are disulfide bridges seen?

Answer 19

tertiary, quaternary

Question 20

What assist in protein folding?

Answer 20

chaperones and chaperonins

Question 21

binds to nascent polypeptide chain as its synthesis is being completed and prevents uncompleted chains from folding prematurely; they also help to unfold the protein before being inserted into membranes

Answer 21

hsp70

Question 22

barrel shaped proteins which allow unfolded proteins and nascent proteins to enter and its hydrophobic interior repels water and serves as template for protein folding

Answer 22

hsp60

Question 23

what does the cis-trans isomerase do?

Answer 23

it converts a trans peptide bond preceding a proline into the cis conformation, which is well suited for making hairpin turns

Question 24

What does the protein disulfide isomerase do?

Answer 24

it breaks and reforms disulfide bonds between the SH groups of two cysteine residues in transient structures formed during the folding process.

Question 25

What are proteins degraded by?

Answer 25

ubiquitin-proteasome degradation system

Question 26

What is AB42?

Answer 26

a degradation product of amyloid precursor protein that leads to neuronal damage