Folding

Question 1

HSP 60

Answer 1

GroEL (body)

Question 2

HSP 10

Answer 2

GroES (cap)

Question 3

Urea in Anfinsen

Answer 3

chaotropic agent - disrupt

non-covalent bonds (H bonds)

Question 4

Beta-mercaptoethanol (2ME) in Anfinsen

Answer 4

reducing agent - disrupt disulfide bonds

Question 5

Anfinsen exp steps

Answer 5

• used Ribonuclease A
• added Urea, disrupts non-covalent H bonds
• reduced to 8 Cys residues
• removed both
• folds back to native state

Question 6

result of Anfinsen

Answer 6

Ribonuclease A regains native state, sequence -> structure

Question 7

GroEL complex structure

Answer 7

2 rings per complex, 7 subunits per ring

Question 8

folding motifs in single GroEL subunit

Answer 8

3 domains:
apical- A/B motifs
intermediate- all A motifs
equatorial- all A motifs

Question 9

folding motifs in GroES complex

Answer 9

antiparallel B sheets, mobile loop and B hairpin

Question 10

chaperones

Answer 10

proteins that interact w/partially/incorrectly folded polypeptides, facilitates correct folding pathway

Question 11

eg of chaperones

Answer 11

GroEL/GroES

Question 12

GroEL-GroES complex steps

Answer 12

• GroEL recognizes exposed HPhob pocket of unfolded protein
• ATP binds to all 7 subunits of one ring, GroEs caps protein within GroEL
• Complex folds protein
• ATP converts to ADP, folded protein released
• Process repeats with other ring

Question 13

function of GroEL-GroES complex

Answer 13

targets exposed HPhob pockets on unfolded proteins, encapsulates unfolded protein, protein can fold w/out risk of aggregation

Question 14

minimum attributes of native folding state

Answer 14

USA (unique, stable, accessible)

Question 15

Levinthal’s Paradox

Answer 15

folding deterministic, mathematically impossible to try all folding conformations

Question 16

protein folding funnel

Answer 16

model which illustrates the energies landscape and conformational space available for a protein to fold

Question 17

advantage of having certain correctly pre-folded segments

Answer 17

no need to sample all folding conformations, secondary structure can form more easily bc arise from small amount of AA’s, these secondary structures can interact with one another

Question 18

GroEL apical domain purpose

Answer 18

opening of chaperone to unfolded protein, flexible, HPhob

Question 19

GroEL intermediate domain purpose

Answer 19

allow ATP and ADP diffusion, flexible hinges

Question 20

GroEL equatorial domain purpose

Answer 20

ATP binding site, stabilizes double ring structure