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If space is provided, bulky modification on the rim of Azurin’s β-barrel results in folded protein
- Source :
- FEBS Letters. (2):209-214
- Publisher :
- Federation of European Biochemical Societies. Published by Elsevier B.V.
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Abstract
- Pseudomonas aeruginosa azurin is a blue-copper protein with a beta-barrel fold. Here we report that, at conditions where thermal unfolding of apo-azurin is reversible, the reaction occurs in a single step with a transition midpoint (T(m)) of 69 degrees C (pH 7). The active-site mutation His117Gly creates a cavity in the beta-barrel near the surface but does not perturb the overall fold (T(m) of 64 degrees C, pH 7). Oxidation of the active-site cysteine (Cysteine-112) in wild-type azurin, which occurs readily at higher temperatures, results in a modified protein that cannot adopt a native-like structure. In sharp contrast, Cysteine-112 oxidation in His117Gly azurin yields a modified apo-azurin that appears folded and displays cooperative, reversible unfolding (T(m) approximately 55 degrees C, pH 7). We conclude that azurin's beta-barrel is a rigid structural element that constrains the structure of its surface; a bulky modification can only be accommodated if complementary space is provided.
- Subjects :
- Thermal denaturation
Protein Denaturation
Biophysics
β-barrel stability
Single step
Crystallography, X-Ray
Biochemistry
Protein Structure, Secondary
Differential scanning calorimetry
Structural Biology
Azurin
Genetics
Cysteine oxidation
Cysteine
Protein folding
Molecular Biology
Calorimetry, Differential Scanning
Chemistry
Circular Dichroism
Temperature
Cell Biology
Crystallography
Mutation
Pseudomonas aeruginosa
Apoproteins
Oxidation-Reduction
Subjects
Details
- Language :
- English
- ISSN :
- 00145793
- Issue :
- 2
- Database :
- OpenAIRE
- Journal :
- FEBS Letters
- Accession number :
- edsair.doi.dedup.....ee5875c21cb1a1dc41251599db187b66
- Full Text :
- https://doi.org/10.1016/S0014-5793(02)03505-6