BIOLOGY 2B03 Study Guide - Winter 2018, Comprehensive Midterm Notes - Ubiquitin, Tissue Paper, Spinocerebellar Ataxia
12 Oct 2018
School
Department
Course
Professor
BIOLOGY 2B03
MIDTERM EXAM
STUDY GUIDE
Fall 2018
CHAPERONES - Correct misfolding:
Aggregates form when proteins are misfolded
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Chaperones: 1) Monomeric molecular chaperones & 2) Multimeric chaperonin complex
Monomeric molecular chaperones
1.
Bind to hydrophobic R groups of amino acid residues on a polypeptide = prevent
protein from incorrect folding when the hydrophobic regions interact with the
aqueous environment and other proteins that would cause them to fold
prematurely (within a protein OR other proteins)
Ex. Hsp70, BiP, DnaK
Hsp70 found in cytosol and mitochondria of eukaryotic cells
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BiP found in endoplasmic reticulum
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DnaK found in bacterial cells
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Hsp70 = "heat shock proteins" = expressed at high levels when STRESS = i.e.
elevated temperature
@ higher temperatures (where proteins can denature) = cell makes heat
shock proteins which help to refold denatured proteins
§
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Hsp70 has 2 domains
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Nucleotide binding domain
1.
Substrate-binding domain
2.
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Substrate = unfolded protein that is leaving the ribosome
A cluster of hydrophobic residues on the substrate is exposed to the aqueous cytosol
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Then Hsp70's hydrophobic patches (residues) then bind ON the unfolded proteins
(ATP + H20) + DNAJ/Hsp40 ---GrpE/BAG1---> ADP + P
It is the hydrolysis from ATP to ADP that changes the conformation of
the Hsp70 chaperone = allows the unfolded protein to fold properly
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Then new ATP comes in to the fill the nucleotide-binding domain
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Folded protein is released
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Hsp70 is ready binds to another unfolded protein
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○
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(A
G
D
Nucleotide
binding domain
"su
Module 2 Lecture 1p
Monday, January 15, 2018
9:18 PM
find more resources at oneclass.com
find more resources at oneclass.com
(ATP + H20) --> ADP + P = hydrolysis
GrpE/BAG1= nucleotide exchange factors
DNAJ/Hsp40 = cotransporter proteins that stimulates hydrolysis
ain
Substrate-
binding domain
"substrate" = the unfolded protein from the ribosome
ATP
Hydrophobic
patches
PROTEIN BINDING
1.
2. DNAJ/Hsp40
AD
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Chaperones: 1) monomeric molecular chaperones & 2) multimeric chaperonin complex. Hsp70 found in cytosol and mitochondria of eukaryotic cells. Hsp70 = "heat shock proteins" = expressed at high levels when stress = i. e. elevated temperature. @ higher temperatures (where proteins can denature) = cell makes heat shock proteins which help to refold denatured proteins. Substrate = unfolded protein that is leaving the ribosome. A cluster of hydrophobic residues on the substrate is exposed to the aqueous cytosol. Then hsp70"s hydrophobic patches (residues) then bind on the unfolded proteins (atp + h20) + dnaj/hsp40 ---grpe/bag1---> adp + p. It is the hydrolysis from atp to adp that changes the conformation of the hsp70 chaperone = allows the unfolded protein to fold properly. Then new atp comes in to the fill the nucleotide-binding domain. Hsp70 is ready binds to another unfolded protein. Nucleotide binding domain (atp + h20) --> adp + p = hydrolysis. "substrate" = the unfolded protein from the ribosome.
