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X-ray absorption studies on catechol 2,3-dioxygenase from Pseudomonas putida mt2
I Bertini1, F Briganti, S Mangani
1Dipartimento di Chimica, Università di Firenze, Italy.
Biochemistry
|September 6, 1994
Summary
X-ray absorption spectroscopy revealed the active site structure of iron(II) catechol 2,3-dioxygenase. The enzyme
Area of Science:
- Biochemistry
- Structural Biology
- Spectroscopy
Background:
- Iron(II) catechol 2,3-dioxygenase is crucial for degrading aromatic compounds.
- Understanding its active site structure is key to enzyme function and inhibitor design.
Purpose of the Study:
- To investigate the active site structure of iron(II) catechol 2,3-dioxygenase from Pseudomonas putida mt2.
- To determine the coordination environment of the ferrous ion in both native and inhibited enzyme forms.
Main Methods:
- X-ray absorption spectroscopy (XANES and EXAFS)
- Multiple scattering theory analysis
- Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy
Main Results:
- EXAFS data indicate iron(II) is coordinated by five or six N/O atoms.
- Histidine residues are present in the iron's coordination sphere.
- Inhibitor binding does not significantly alter metal geometry but slightly shortens metal-donor bond distances.
Conclusions:
- The active site structure of iron(II) catechol 2,3-dioxygenase is elucidated.
- Direct binding of 2-chlorophenol to the iron center is confirmed.
- Enzyme structure is robust, with minor adjustments upon inhibitor interaction.