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Catalytic Site Atlas

CSA LITERATURE entry for 1elq

SpeciesSynechocystis sp. (Bacteria)
E.C. Number (IntEnz) -.-.-.-
CSA Homologues of 1elqThere are 22 Homologs
CSA Entries With UniProtID
CSA Entries With EC Number -.-.-.-
PDBe Entry 1elq
PDBSum Entry 1elq
MACiE Entry 1elq

Literature Report

IntroductionCystine C-S lyase(C-DES) directs FeS cluster insertion into Synechocystis apoferridoxin in vivo . The observation of a persulfidic intermediate mimics the NifS PLP dependent L-Cysteine desulphurase, although C-DES is missing the largely conserved active site cysteine associated with NifS enzymes. The mechanism for C-DES persulphide formation offers an alternative pathway for the formation of S(0), although the mode of transport of the elemental sulphur has yet to be determined.
MechansimFirstly the PLP cofactor forms a Schiff base linkage to Lys223. His 114 initiates transaldimation, deprotonating the substrate amino acid group and allowing nucleophilic attack at the aldimine group. Lys 233 deprotonates at C alpha, forming a quinonoid intermediate. Subsequent protonation of the leaving group by Lys 233 results in conjugate elimination of a cysteine persulphide group and PLP-amino acrylate. Stabilisation of the reactive persulphide group by controlling the electrostatics within the active site allows the enzyme to act as an activated sulphur source.

Catalytic Sites for 1elq

Literature References

Notes:There is no designated EC code, so I have allocated one from the EC website knowing the substrate and products involved.
Clausen T
Crystal structure of the cystine C-S lyase from Synechocystis: stabilization of cysteine persulfide for FeS cluster biosynthesis.
Proc Natl Acad Sci U S A 2000 97 3856-3861
PubMed: 10760256