Thermodynamic analysis of a molecular chaperone binding to unfolded protein substrates.
Abstract
Molecular chaperones are a highly diverse group of proteins that recognize and bind
unfolded proteins to facilitate protein folding and prevent nonspecific protein aggregation.
The mechanisms by which chaperones bind their protein substrates have been studied
for decades. However, there are few reports about the affinity of molecular chaperones
for their unfolded protein substrates. Thus, little is known about the relative binding
affinities of different chaperones and about the relative binding affinities of chaperones
for different unfolded protein substrates. Here we describe the application of SUPREX
(stability of unpurified proteins from rates of H-D exchange), an H-D exchange and
MALDI-based technique, in studying the binding interaction between the molecular chaperone
Hsp33 and four different unfolded protein substrates, including citrate synthase,
lactate dehydrogenase, malate dehydrogenase, and aldolase. The results of our studies
suggest that the cooperativity of the Hsp33 folding-unfolding reaction increases upon
binding with denatured protein substrates. This is consistent with the burial of significant
hydrophobic surface area in Hsp33 when it interacts with its substrate proteins. The
SUPREX-derived K(d) values for Hsp33 complexes with four different substrates were
all found to be within the range of 3-300 nM.
Type
Journal articleSubject
AnimalsCitrate (si)-Synthase
Escherichia coli Proteins
Fructose-Bisphosphate Aldolase
Heat-Shock Proteins
L-Lactate Dehydrogenase
Malate Dehydrogenase
Molecular Chaperones
Protein Binding
Protein Folding
Rabbits
Substrate Specificity
Swine
Thermodynamics
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https://hdl.handle.net/10161/4016Published Version (Please cite this version)
10.1021/bi902010tPublication Info
Xu, Ying; Schmitt, Sebastian; Tang, Liangjie; Jakob, Ursula; & Fitzgerald, Michael
C (2010). Thermodynamic analysis of a molecular chaperone binding to unfolded protein substrates.
Biochemistry, 49(6). pp. 1346-1353. 10.1021/bi902010t. Retrieved from https://hdl.handle.net/10161/4016.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Michael C. Fitzgerald
Professor of Chemistry
Dr. Fitzgerald’s research group is focused on studies of protein folding and function.
The group utilizes a combination of covalent labeling strategies (e.g. protein amide
H/D exchange and methionine oxidiation) and mass spectrometry techniques to investigate
the thermodynamic properties of protein folding and ligand binding reactions. Current
research efforts involve: (1) the development new biophysical methods that enable
protein folding and stability measurements to be performed on the prote

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