Exam 4 Part 2

Question 1

Protein conformation

Answer 1

1. hydrophobic residues inside
2. form alpha helices and beta sheets
3. combine with cofactors
4. become covalently modified at specific sites
5. form quaternary structures with subunits

Question 2

chaperones

Answer 2

a set of proteins that help cellular proteins fold correctly or refold correctly

Question 3

Hsp

Answer 3

heat shock proteins
made in large quantities at high temps
1. they bind to hydrophobic patches
2. require ATP hydrolysis

Question 4

hsp70

Answer 4

1. bind to exposed hydrophobic amin acid

2. appear to prevent hydrophobic regions from nonspecific conformation

Question 5

hsp60

Answer 5

1. aka chaperonin
2. after a protein has been synthesized
3. forms basket with hydrophobic sides
4. confinement gives protein time to refold w/o interference of other cellular proteins

Question 6

proteasome parts

Answer 6

3 parts,
2 19S regulatory particles on each end
1 20S core particle in the middle

Question 7

subunits of the core

Answer 7

some of the subunits of the core are proteases that hydrolyze peptide bonds

Question 8

digestive proteases

Answer 8

trypsin, chymotrypsin

Question 9

trypsin

Answer 9

carboxyl side of lysine and arginine (positively-charged residues

Question 10

chymotrypsin

Answer 10

carboxyl side of tyrosine, tryptophan and phenylalanine (all contain aromatic rings)

Question 11

20S core structure

Answer 11

7 alphas
7 betas
7 betas
7 alphas
1. trypsin-like activity
2. chymotrypsin-like activity
3. post-glutamyl-peptide hydrolytic activity

Question 12

regulatory subunit 19S ends of protease

Answer 12

functions

1. substrate unfolding
2. substrate recognition
3. ubiquitin releasing

Question 13

unfolding in base of 19S

Answer 13

T1-T6 in base

hexameric unfoldase

Question 14

AAA protein definition

Answer 14

ATPase Associated with diverse cellular Activities

Question 15

substrate unfolding

Answer 15

unfoldase contains ATP
ATP hydrolyzes ATP to pull the protein in
unfoldase is an AAA protein

Question 16

substrate recognition

Answer 16

recognizes polyubiquitin

Question 17

ubiquitination

Answer 17

1. only attaches to lysine
2. attaches with glycine 76 via isopeptide bond
3. E1 enzyme binds to ubiquitin with high energy thioester bond, activates ubiquitin
4. E2 and E3 bind to E1
5. ubiquitin transfers to cysteine on E2
6. E1 leaves, E3 used to recognize target protein
7. E2 transfers ubiquitin to protein

Question 18

RING domain E3

Answer 18

transfers ubiquitin directly from E2 to protein

Question 19

HECT domain E3

Answer 19

ubiquitin transfers to E3 before transferring to the protein

Question 20

mono-ubiquitylation

Answer 20

histone regulation

Question 21

multi-ubiquitylation

Answer 21

endocytosis

Question 22

polyubiquitylation

Answer 22

proteasomal degradation

DNA repair

Question 23

stack of Beta sheets resistant to proteolysis

Answer 23

amyloid

Question 24

disease caused by incorrectly folded protein aggregates

Answer 24

“Mad Cow” Creutzfeldt-Jacob disease
Alzheimer’s
Huntington’s

Question 25

Dr. George Glenner thought the amyloidogenic protein A-beta accumulating could be causing

Answer 25

Alzheimer’s Disease