The interaction of 5'-adenylylsulfate reductase from Pseudomonas aeruginosa with its substrates.
Biochim Biophys Acta
; 1710(2-3): 103-12, 2005 Dec 20.
Article
en En
| MEDLINE
| ID: mdl-16289027
ABSTRACT
APS reductase from Pseudomonas aeruginosa has been shown to form a disulfide-linked adduct with mono-cysteine variants of Escherichia coli thioredoxin and Chlamydomonas reinhardtii thioredoxin h1. These adducts presumably represent trapped versions of the intermediates formed during the catalytic cycle of this thioredoxin-dependent enzyme. The oxidation-reduction midpoint potential of the disulfide bond in the P. aeruginosa APS reductase/C. reinhardtii thioredoxin h1 adduct is -280 mV. Site-directed mutagenesis and mass spectrometry have identified Cys256 as the P. aeruginosa APS reductase residue that forms a disulfide bond with Cys36 of C. reinhardtii TRX h1 and Cys32 of E. coli thioredoxin in these adducts. Spectral perturbation measurements indicate that P. aeruginosa APS reductase can also form a non-covalent complex with E. coli thioredoxin and with C. reinhardtii thioredoxin h1. Perturbation of the resonance Raman and visible-region absorbance spectra of the APS reductase [4Fe-4S] center by either APS or the competitive inhibitor 5'-AMP indicates that both the substrate and product bind in close proximity to the cluster. These results have been interpreted in terms of a scheme in which one of the redox-active cysteine residues serves as the initial reductant for APS bound at or in close proximity to the [4Fe-4S] cluster.
Buscar en Google
Colección:
01-internacional
Asunto principal:
Pseudomonas aeruginosa
/
Tiorredoxinas
/
Cisteína
/
Oxidorreductasas actuantes sobre Donantes de Grupos Sulfuro
Idioma:
En
Revista:
Biochim Biophys Acta
Año:
2005
Tipo del documento:
Article
País de afiliación:
Estados Unidos