Cloning, biochemical and phylogenetic characterizations of gamma-glutamylcysteine synthetase from Anabaena sp. PCC 7120.

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Ashida H, Sawa Y, Shibata H

Cloning, biochemical and phylogenetic characterizations of gamma-glutamylcysteine synthetase from Anabaena sp. PCC 7120.

Plant Cell Physiol. 2005 Apr;46(4):557-62. Epub 2005 Feb 2.

PubMed ID
15695431 [ View in PubMed
]
Abstract

Gamma-glutamylcysteine synthetase (EC 6.3.2.2, gamma-GCS) catalyzes the first step of glutathione synthesis: l-Glu + l-Cys + ATP = gamma-l-glutamyl-l-cysteine (gamma-GC) + ADP + Pi. We have cloned the gene alr3351 of Anabaena sp. PCC 7120, expressed the recombinant enzyme in Escherichia coli, and characterized its product as gamma-GCS by analyzing gamma-GC production, ADP formation and Pi release. Apparent Km values for l-Glu, ATP and l-Cys were estimated to be 0.82, 0.23 and 0.14 mM, respectively. Glutathione and l-buthionine sulfoximine were inhibitors with Ki values of 6.5 and 29.3 mM, respectively. The molecular mass of Anabaena gamma-GCS was estimated to be 43.4 kDa by SDS-PAGE and matrix-assisted laser desorption/ionization time of flight mass spectrometry. The important sequence for the activity of plant gamma-GCS was found in alpha-proteobacterial gamma-GCSs but not in cyanobacterial enzymes, suggesting that the cyanobacterial gamma-GCS gene is not the primary progenitor for the plant genes.

DrugBank Data that Cites this Article

Drug Targets
DrugTargetKindOrganismPharmacological ActionActions
CysteineGlutamate--cysteine ligase catalytic subunitProteinHumans
Unknown
Not AvailableDetails
CysteineGlutamate--cysteine ligase regulatory subunitProteinHumans
Unknown
Not AvailableDetails