Question 1
Question
Which of the following is not a role of the DNAK/Hsp70 superfamily?
Answer
-
Stabilise nascent polypeptides
-
Repaor heat shocked proteins
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Preserve folding proteins
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Protein transport
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Protein degredation
Question 2
Question
Hsp70s (unlike DNAK's) do not require chaperones
Question 3
Question
What is the role of DNAJ/Hsp40 when combined with DNAK/Hsp70
Question 4
Question
DNAK/Hsp70 need NEF's in order to function
Question 5
Question
Where is the Hsp70/DNAK binding domain for ATP?
Answer
-
N-terminus
-
Core
-
C- terminus
Question 6
Question
Name the subdomains of the ATPase found in DNAK/Hsp70
Question 7
Question
What increases the ATPase activity of the ATP binding domain?
Question 8
Question
The core substrate binding domain has an affinity for what?
Answer
-
Neutral, hydrophobic aa
-
Acidic, polar aa
-
Basic, polar aa
Question 9
Question
The C-terminus of DNAK/Hsp 70 acts as a 'lid' for the protein
Question 10
Question
When ATP is hydrolysed in DNAK/Hsp70, where does the C-terminus bind to?
Answer
-
The N-terminus
-
The core
-
It doesn't move at all
-
Over the bound substrate
Question 11
Question
Without the assistance of DNAJ/Hsp40, the ATPase in DNAK/Hsp70 works too slowly for the C-terminus to trap the bound substrate
Question 12
Question
Hsp70/DNAK's preferred binding pattern is 15 aa long
Question 13
Question
What are the 'Flanking' residues (1-4, 9-13) of Hsp70's preferred binding site made of?
Question 14
Question
The preferred residue for the -Core- of Hsp70's preferred binding site is Valine
Question 15
Question
What other residues can make up the 'core' of the preferred binding site/
Question 16
Question
How does this 'Preferred Binding Patter' for Hsp70 help direct the protein?
Answer
-
In properly folded proteins, the hydrophobic stretch is hidden, and so only nascent/denatured proteins have the exposed residues for Hsp70 to bind to
-
In nascent/denatured proteins, these hydrophobic residues will be added by Hsp40, so it can recognise them
-
Stretches with the core residues are removed during protein folding, so only nascent polypeptides have them
Question 17
Question
What is the role of the J domain in a Hsp40?
Answer
-
Contain the HPD peptide needed to boost Hsp40's ATPase
-
Gly/Phe rich linker for positioning
-
Dimerisation domain
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Zn+ 'finger' for substrate binding
Question 18
Question
The role of the Gly/Phe rich linker does what?
Answer
-
Makes DNAJ/Hsp40 flexible enough to bind to its respective protein
-
Makes DNAJ/Hsp40 a more effective ATPase
-
Allows DNAJ/Hsp40 to locate its respective DNAK/Hsp70
Question 19
Question
The Zinc 'Finger' is for substrate binding
Question 20
Question
Which amino acids make up the HPD domain?
Answer
-
Histadine
-
Proline
-
Aspartate
-
Leucine
-
Glycine
Question 21
Question
The Znc finger of DNAJ/Hsp40 can interact with the nascent polypeptide and bring it to the DNAK/Hsp70
Question 22
Question
What is the sequence of the Zinc 'finger'?
Answer
-
CXXCXGXG
-
GXXGXCXC
-
GXXCXGXC
-
CXXGXCXG
Question 23
Question
The C-terminus of Hsp40 is for tetramerisation
Question 24
Question
What effect does the GEF factor binding have on the Hsp70/Hsp40 complex?
Question 25
Question
When the substrate & Hsp40 bind to Hsp70, the GEF factor also binds
Question 26
Question
How is the nascent polypeptide transferred from the DNAJ site to the DNK site?
Answer
-
The G/F domain is flexible enough to bind to the DNAK site and pull it in for transfer
-
The J domain is pulled like a thread through the ATPase, bringing the two sites close enough together for transfer
-
The dimerisation of the DNAJ pulls the two sites close together
Question 27
Question
In which of the following is Prefoldin found?
Answer
-
Archea
-
Prokaryotes
-
Eukaryotes
Question 28
Question
Prefoldin can act as a substitute for Hsp70 if the organsim doesn't have the latter
Question 29
Question
Prefoldin is ATP dependent
Question 30
Question
Prefolding is a...
Question 31
Question
What is the role of Preofoldin in Archea?
Answer
-
Captures nascent polypeptides and binds them to Gro-El
-
Captures nascent polypeptides and binds them to CCT
-
Captures nascent polypeptides and binds them to SSA
Question 32
Question
In Eukaryotes, prefoldin might be specific for the folding of what?
Answer
-
Actin/tubulin
-
CCT
-
Hsp40
-
Hsp70
Question 33
Question
In archea there are 6 Prefoldin genes (Grim1-6) in Eukaryotes there are 2 (Gimalpha and Gimbeta)
Question 34
Question
Which of the following describe Prefoldin
Question 35
Question
There are 3.5 amino acid residues per helical turn of the coiled coil helices in Prefoldin (not 3.6)
Question 36
Question
The subunits forming the dimerisation interface of the below molecule are what?
Question 37
Question
Where do the non-native proteins bind to Prefoldin?
Answer
-
Exposed hydrophobic residues in the distal ends of the 'tentacle'
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Exposed hydrophobic residues in the proximal ends of the 'tentacle'
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Exposed hydrophobic residues at the top of the 'tentacle'