6gmo

Plant glutamate cysteine ligase (GCL) in complex with non-reducing GSH (GSM)

spinqualitylabelsall models 6gmo, resolution 1.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6gmo is a 2 chain structure with sequence from Brassica juncea. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.75Å Ligands: ACT, GOL, GSM, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function GSH1_BRAJU Participates in the detoxification process. Publication Abstract from PubMed Plant gamma-glutamylcysteine ligase (GCL), catalyzing the first and tightly regulated step of glutathione (GSH) biosynthesis, is redox-activated via formation of an intramolecular disulfide bond. In vitro, redox-activation of recombinant GCL protein causes formation of homo-dimers. Here, we have investigated whether dimerization occurs in vivo and if so whether it contributes to redox-activation. FPLC analysis indicated that recombinant redox-activated WT (wild type) AtGCL dissociates into monomers at concentrations below 10(-6) M, i.e. below the endogenous AtGCL concentration in plastids, which was estimated to be in the micromolar range. Thus, dimerization of redox-activated GCL is expected to occur in vivo To determine the possible impact of dimerization on redox-activation, AtGCL mutants were generated in which salt bridges or hydrophobic interactions at the dimer interface were interrupted. WT AtGCL and mutant proteins were analyzed by non-reducing SDS-PAGE to address their redox state and probed by FPLC for dimerization status. Furthermore, their substrate kinetics (K M, V max) were compared. The results indicate that dimer formation is not required for redox-mediated enzyme activation. Also, crystal structure analysis confirmed that dimer formation does not affect binding of GSH as competitive inhibitor. Whether dimerization affects other enzyme properties, e.g. GCL stability in vivo, remains to be investigated. Plant glutathione biosynthesis revisited: redox-mediated activation of glutamylcysteine ligase does not require homo-dimerization.,Yang Y, Lenherr ED, Gromes R, Wang S, Wirtz M, Hell R, Peskan-Berghofer T, Scheffzek K, Rausch T Biochem J. 2019 Apr 15;476(7):1191-1203. doi: 10.1042/BCJ20190072. PMID:30877193 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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