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Beware of proteins in DMSO
1Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa.
Biochimica Et Biophysica Acta
|June 24, 1991
Summary
Dimethyl sulfoxide (DMSO) alters protein secondary structure, causing unfolding and aggregation in structured proteins like myoglobin. Unstructured proteins like alpha-casein show disrupted hydrogen bonds with increasing DMSO concentrations.
Area of Science:
- Biochemistry
- Structural Biology
- Spectroscopy
Background:
- Proteins adopt specific secondary structures (alpha-helices, beta-sheets) crucial for function.
- Dimethyl sulfoxide (DMSO) is a common solvent with known effects on biomolecules.
- Understanding solvent effects on protein structure is vital for various applications.
Purpose of the Study:
- To investigate the impact of varying dimethyl sulfoxide (DMSO) concentrations on protein secondary structure.
- To elucidate the mechanisms of DMSO-induced protein structural changes using Fourier transform infrared spectroscopy.
Main Methods:
- Fourier transform infrared (FTIR) spectroscopy was employed.
- Representative proteins with alpha-helical, beta-sheet, and disordered structures were studied.
- Varying concentrations of DMSO in D2O were used as solvent conditions.
Main Results:
- DMSO induced significant perturbations in protein secondary structures.
- Moderate DMSO concentrations led to destabilization and aggregation (beta-sheet formation) in structured proteins.
- High DMSO concentrations caused complete unfolding, indicated by free amide groups.
Conclusions:
- DMSO disrupts intramolecular and intermolecular hydrogen bonds, leading to partial or complete protein unfolding.
- Protein aggregation can occur at moderate DMSO concentrations, followed by dissociation at higher concentrations.
- DMSO reduces the thermal stability of proteins even at low concentrations.