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Reductive cleavage of S-adenosylmethionine by biotin synthase from Escherichia coli.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2002 Apr 19; Vol. 277 (16), pp. 13449-54. Date of Electronic Publication: 2002 Feb 07. - Publication Year :
- 2002
-
Abstract
- Biotin synthase (BioB) catalyzes the insertion of a sulfur atom between the C6 and C9 carbons of dethiobiotin. Reconstituted BioB from Escherichia coli contains a [4Fe-4S](2+/1+) cluster thought to be involved in the reduction and cleavage of S-adenosylmethionine (AdoMet), generating methionine and the reactive 5'-deoxyadenosyl radical responsible for dethiobiotin H-abstraction. Using EPR and Mössbauer spectroscopy as well as methionine quantitation we demonstrate that the reduced S = 1/2 [4Fe-4S](1+) cluster is indeed capable of injecting one electron into AdoMet, generating one equivalent of both methionine and S = 0 [4Fe-4S](2+) cluster. Dethiobiotin is not required for the reaction. Using site-directed mutagenesis we show also that, among the eight cysteines of BioB, only three (Cys-53, Cys-57, Cys-60) are essential for AdoMet reductive cleavage, suggesting that these cysteines are involved in chelation of the [4Fe-4S](2+/1+) cluster.
- Subjects :
- Biotin chemistry
Cysteine chemistry
Electron Spin Resonance Spectroscopy
Kinetics
Methionine chemistry
Models, Chemical
Mutation
Spectroscopy, Mossbauer
Sulfurtransferases chemistry
Time Factors
Biotin analogs & derivatives
Escherichia coli enzymology
S-Adenosylmethionine chemistry
S-Adenosylmethionine pharmacology
Sulfurtransferases metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 277
- Issue :
- 16
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 11834738
- Full Text :
- https://doi.org/10.1074/jbc.M111324200