Question 1
Question
Chaperonins are for nascent proteins that don't fold independently or interact with other cytosolic chaperones
Question 2
Question
To what is the arrow pointing on the Gro-El monomer?
Question 3
Question
How many monomers make up Gro-El?
Answer
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14- 7 in each layer
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12- 6 in each layer
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10- 5 in each layer
Question 4
Question
Gro-Es is made of 7 monomers
Question 5
Question
Why does Gro-Es bind to close the cavity?
Answer
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Creates a space away from crowded cytosol for protein binding
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Creates a highly acidic environment for proteins to fold in
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Allows protein to fold in highly saline environment
Question 6
Question
ATP & Gro-Es bind at separate points in the protein folding cycle
Question 7
Question
The nascent protein will bind at the monomer level _ side with ADP and Gro-Es bound
Question 8
Question
Once Gro-Es and ATP are bound, the protein refolds for _ seconds whilst the ATP is hydrolysed
Question 9
Question
When the protein has folded properly, what happens?
Answer
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A nascent polypeptide binds to the end opposite the Gro-Es and ADP, causing the cycle to repeat itself at the other end of the protein
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Gro-Es dissociates, releasing the folded protein
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The ADP is released and replaced with ATP
Question 10
Question
The CCT and Gro-El cycles are basically the same, but Gro-El has flexible extensions that CCT does not
Question 11
Question
What is bacterial homologue of the Hsp100 family?
Question 12
Question
Hsp100 and its bacterial homologue are hexamers
Question 13
Question
Clp100 and its bacterial homologue do what?
Question 14
Question
What is the difference between Class 1 & Class 2 Hsp100 proteins?
Question 15
Question
How do you tell apart Class 1 and Class 2
Answer
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Class 1 has 2 ATPase sites, Class 2 has 1
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Class 1 has 1 ATPase site, Class 2 has 2
Question 16
Question
Hsp100's consist of one/two sets of hexamers
Question 17
Question
The ATP is hydrolysed in Hsp100's/Clp proteins to allow what?
Answer
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To drive conformational changes in aromatic loops that interact with the substrate
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To provide energy to break the peptide bonds in the protein to be unfolded
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To provide energy to posh apart poorly stacked peptides
Question 18
Question
When ClpA and ClpP interact, what is the role of the supercomplex?
Question 19
Question
Hsp90 chaperones are required for what?
Answer
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High temperature growth
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High salinity growth
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High pH growth
Question 20
Question
Hsp90 are ATP dependent monomers
Question 21
Question
What is found on the N-terminus of a Hsp90 protein?
Answer
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ATP binding site
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Substrate binding domain
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Dimerisation domain
Question 22
Question
The dimerisation domain of Hsp90 occurs at the C terminus
Question 23
Question
ATPase inhibitors of Hsp90 target which part of the protein?
Answer
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N terminus
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C terminus
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Middle
Question 24
Question
The binding of ATP causes the ATP 'lid' to close and the dimer to split
Question 25
Question
Name the conformational changes that occur after ATP binds
Answer
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N-terminals undergo Beta strand exchange
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N-terminals undergo Alpha helix exchange
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Rotation of N domain (relative to middle) to allow meeting of dimerisation domains
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Rotation of C domain (relative to middle) to allow meeting of dimerisation domains
Question 26
Question
What is the role of the core domain of Hsp90 (with regards to the ATPase)
Answer
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It's flexible enough that it completes the dimerisation site and allows ATP hydrolysis to occur
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It's flexible enough that it completes the ATPase site and allows ATP hydrolysis to occur
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Interacting with the gamma phosphate of ATP
Question 27
Question
The conformational changes of Hsp90 are thought to be brought about by client proteins
Question 28
Question
cd37/p50 inhibit Hsp90 by what process?
Question 29
Question
Sti/HOP bind to the N-terminal of Hsp90 & Hsp70, binding them together as a potent inhibitor
Question 30
Question
Aha activates Hsp90 how?
Answer
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Activates ATPase activity by promoting open state of of catalytic loop
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Causing N-terminal alignment for dimerisation
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Physically holding the active site open
Question 31
Question
Spa1 both inhibits and stimulates ATPase activity, leading to an overall slowing of ATPase in Hsp90
Question 32
Question
How does Sba activate ATPase activity?
Answer
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Interacts with the middle domain of Hsp90 and modulates the catalytic loop of this domain
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Increases the affinity of the dimerisation sites for each other, completing the ATPase sites more stably
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Increases the affinity for the binding site for ATP
Question 33
Question
Hsp90 can be used to activate steroid receptors and kinases