Abstract
To visualize the formation of disulfide bonds in living cells, a pair of redox-active cysteines was introduced into the yellow fluorescent variant of green fluorescent protein. Formation of a disulfide bond between the two cysteines was fully reversible and resulted in a >2-fold decrease in the intrinsic fluorescence. Inter conversion between the two redox states could thus be followed in vitro as well as in vivo by non-invasive fluorimetric measurements. The 1.5 A crystal structure of the oxidized protein revealed a disulfide bond-induced distortion of the beta-barrel, as well as a structural reorganization of residues in the immediate chromophore environment. By combining this information with spectroscopic data, we propose a detailed mechanism accounting for the observed redox state-dependent fluorescence. The redox potential of the cysteine couple was found to be within the physiological range for redox-active cysteines. In the cytoplasm of Escherichia coli, the protein was a sensitive probe for the redox changes that occur upon disruption of the thioredoxin reductive pathway.
| Original language | English |
|---|---|
| Journal | E M B O Journal |
| Volume | 20 |
| Issue number | 21 |
| Pages (from-to) | 5853-62 |
| Number of pages | 10 |
| ISSN | 0261-4189 |
| DOIs | |
| Publication status | Published - 2001 |
Keywords
- Crystallography, X-Ray
- Cysteine
- Cytoplasm
- Disulfides
- Escherichia coli
- Gene Expression
- Green Fluorescent Proteins
- Luminescent Proteins
- Models, Molecular
- Mutagenesis, Site-Directed
- Oxidation-Reduction
- Protein Engineering
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Spectrometry, Fluorescence
- Thioredoxins