Exam 4 Part 2 Flashcards Preview

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Flashcards in Exam 4 Part 2 Deck (25):
1

Protein conformation

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

2

chaperones

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

3

Hsp

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

4

hsp70

1. bind to exposed hydrophobic amin acid
2. appear to prevent hydrophobic regions from nonspecific conformation

5

hsp60

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

6

proteasome parts

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

7

subunits of the core

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

8

digestive proteases

trypsin, chymotrypsin

9

trypsin

carboxyl side of lysine and arginine (positively-charged residues

10

chymotrypsin

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

11

20S core structure

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

12

regulatory subunit 19S ends of protease

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

13

unfolding in base of 19S

T1-T6 in base
hexameric unfoldase

14

AAA protein definition

ATPase Associated with diverse cellular Activities

15

substrate unfolding

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

16

substrate recognition

recognizes polyubiquitin

17

ubiquitination

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

18

RING domain E3

transfers ubiquitin directly from E2 to protein

19

HECT domain E3

ubiquitin transfers to E3 before transferring to the protein

20

mono-ubiquitylation

histone regulation

21

multi-ubiquitylation

endocytosis

22

polyubiquitylation

proteasomal degradation
DNA repair

23

stack of Beta sheets resistant to proteolysis

amyloid

24

disease caused by incorrectly folded protein aggregates

"Mad Cow" Creutzfeldt-Jacob disease
Alzheimer's
Huntington's

25

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

Alzheimer's Disease