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Circular Dichroism and Magnetic Circular Dichroism Spectroscopic Studies of the Non-Heme Ferrous Active Site in Clavaminate Synthase and Its Interaction with α-Ketoglutarate Cosubstrate
- Source :
- Journal of the American Chemical Society. 120:743-753
- Publication Year :
- 1998
- Publisher :
- American Chemical Society (ACS), 1998.
-
Abstract
- Clavaminate synthase (CS) is one member of a large class of non-heme iron enzymes that require α-ketoglutarate (α-KG) as a cosubstrate. While the majority of this class catalyzes the hydroxylation of unactivated C−H bonds, CS is unusual in that in addition to performing hydroxylation chemistry, it also catalyzes the key oxidative ring closure and desaturation steps in the biosynthetic pathway to the potent β-lactamase inhibitor clavulanic acid. A single non-heme Fe2+ site is responsible for all three of these reactions (hydroxylation, oxidative ring closure, and desaturation), during which 1 equiv of α-KG per reaction is decarboxylated into succinate and CO2. We have applied circular dichroism (CD), magnetic circular dichroism (MCD), and variable-temperature, variable-field (VTVH) MCD spectroscopies to probe the geometric and electronic structure of the ferrous active site in the isozyme CS2 and its interaction with α-KG. CD titration experiments show stoichiometric binding of Fe2+ to the apoenzyme, eithe...
- Subjects :
- chemistry.chemical_classification
Circular dichroism
biology
Magnetic circular dichroism
Stereochemistry
Active site
General Chemistry
Biochemistry
Clavaminate synthase
Catalysis
Cofactor
Ferrous
Hydroxylation
chemistry.chemical_compound
Colloid and Surface Chemistry
Enzyme
chemistry
biology.protein
Subjects
Details
- ISSN :
- 15205126 and 00027863
- Volume :
- 120
- Database :
- OpenAIRE
- Journal :
- Journal of the American Chemical Society
- Accession number :
- edsair.doi...........7c48136b833ca8e65f4aa7110c98f401