Quantitative protein stability measurement in vivo.
The equilibrium between the native and denatured states of a protein can be key to its function and regulation. Traditionally, the folding equilibrium constant has been measured in vitro using purified protein and simple buffers. However, the biological environment of proteins can differ from these in vitro conditions in ways that could significantly perturb stability. Here, we present the first quantitative comparison between the stability of a protein in vitro and in the cytoplasm of Escherichia coli using amide hydrogen exchange detected by MALDI mass spectrometry (SUPREX). The results indicate that the thermodynamic stability of monomeric lambda repressor within the cell is the same as its stability measured in a simple buffer in vitro. However, when the E. coli are placed in a hyperosmotic environment, the in vivo stability is greatly enhanced. The in vivo SUPREX method provides a general and quantitative way to measure protein stabilities in the cell and will be useful for applications where intracellular stability information provides important biological insights.
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- Urea
- Thermodynamics
- Temperature
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Proteins
- Protein Denaturation
- Hydrogen-Ion Concentration
- Hydrogen
- Escherichia coli
- Developmental Biology
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Urea
- Thermodynamics
- Temperature
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Proteins
- Protein Denaturation
- Hydrogen-Ion Concentration
- Hydrogen
- Escherichia coli
- Developmental Biology