6GMO
Plant glutamate cysteine ligase (GCL) in complex with non-reducing GSH (GSM)
Summary for 6GMO
| Entry DOI | 10.2210/pdb6gmo/pdb |
| Descriptor | Glutamate--cysteine ligase, chloroplastic, MAGNESIUM ION, L-GAMMA-GLUTAMYL-S-METHYLCYSTEINYLGLYCINE, ... (6 entities in total) |
| Functional Keywords | glutathione synthesis, ligase, complex |
| Biological source | Brassica juncea |
| Total number of polymer chains | 2 |
| Total formula weight | 102411.47 |
| Authors | Lenherr, E.D. (deposition date: 2018-05-27, release date: 2019-06-19, Last modification date: 2024-11-06) |
| Primary citation | Yang, Y.,Lenherr, E.D.,Gromes, R.,Wang, S.,Wirtz, M.,Hell, R.,Peskan-Berghofer, T.,Scheffzek, K.,Rausch, T. Plant glutathione biosynthesis revisited: redox-mediated activation of glutamylcysteine ligase does not require homo-dimerization. Biochem.J., 476:1191-1203, 2019 Cited by PubMed Abstract: Plant γ-glutamylcysteine ligase (GCL), catalyzing the first and tightly regulated step of glutathione (GSH) biosynthesis, is redox-activated via formation of an intramolecular disulfide bond. , redox-activation of recombinant GCL protein causes formation of homo-dimers. Here, we have investigated whether dimerization occurs 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 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 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 (, ) 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 , remains to be investigated. PubMed: 30877193DOI: 10.1042/BCJ20190072 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.75 Å) |
Structure validation
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