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The Importance of Correct Protein Concentration for Kinetics and Affinity Determination in Structure-function Analysis
Published on: March 18, 2010
Osmolytes as modulators of conformational changes in serpins
M K Chow1, G L Devlin, S P Bottomley
1Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.
Biological Chemistry
|January 5, 2002
Summary
Sarcosine and other osmolytes protect alpha1-antitrypsin from harmful misfolding and aggregation. However, sarcosine does not correct existing misfolded protein structures.
Area of Science:
- Biochemistry
- Molecular Biology
- Proteostasis
Background:
- Protein misfolding and aggregation are implicated in various diseases.
- Misfolding of alpha1-antitrypsin leads to polymer accumulation in hepatocytes, causing alpha1-antitrypsin deficiency, liver cirrhosis, and emphysema.
Purpose of the Study:
- To investigate the effects of naturally occurring osmolytes (sarcosine, glycine betaine, trimethylamine N-oxide) on alpha1-antitrypsin conformational changes.
- To determine the potential of these osmolytes in preventing or correcting alpha1-antitrypsin misfolding.
Main Methods:
- Spectroscopic analysis to monitor conformational changes in alpha1-antitrypsin.
- Thermal stress assays to induce polymerization and inactivation.
- Refolding experiments in the presence of osmolytes.
Main Results:
- All three osmolytes protected native alpha1-antitrypsin against thermal polymerization and inactivation in a concentration-dependent manner.
- Sarcosine stabilized the native conformation, preventing conversion to an intermediate and subsequent polymerization.
- Sarcosine was ineffective in facilitating correct refolding; higher concentrations led to more inactive conformations.
Conclusions:
- Sarcosine can prevent abnormal structural changes in native alpha1-antitrypsin, thus inhibiting polymerization.
- Sarcosine does not facilitate the correct folding of misfolded alpha1-antitrypsin.
- These findings offer insights into managing diseases associated with alpha1-antitrypsin conformational instability.
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