A Papain-Like Enzyme at Work: Native and Acyl- Enzyme Intermediate Structures in Phytochelatin Synthesis.Vivares, D., Arnoux, P., Pignol, D.
(2005) Proc Natl Acad Sci U S A 102: 18848
- PubMed: 16339904
- DOI: 10.1073/pnas.0505833102
- Primary Citation of Related Structures:
- PubMed Abstract:
- Characterization of Phytochelatin Synthase-Like Protein Encoded by Alr0975 from a Prokaryote, Nostoc Sp. Pcc 7120
Tsuji, N., Nishikori, S., Iwabe, O., Shiraki, K., Miyasaka, H., Takagi, M., Hirata, K., Miyamoto, K.
(2004) Biochem Biophys Res Commun 315: 751
- A Cyanobacterial Protein with Similarity to Phytochelatin Synthases Catalyzes the Conversion of Glutathione to Gamma-Glutamylcysteine and Lacks Phytochelatin Synthase Activity
Harada, E., Von Roepenack-Lahaye, E., Clemens, S.
(2004) Phytochemistry 65: 3179
Phytochelatin synthase (PCS) is a key enzyme for heavy-metal detoxification in plants. PCS catalyzes the production of glutathione (GSH)-derived peptides (called phytochelatins or PCs) that bind heavy-metal ions before vacuolar sequestration. The enzyme can also hydrolyze GSH and GS-conjugated xenobiotics ...
Phytochelatin synthase (PCS) is a key enzyme for heavy-metal detoxification in plants. PCS catalyzes the production of glutathione (GSH)-derived peptides (called phytochelatins or PCs) that bind heavy-metal ions before vacuolar sequestration. The enzyme can also hydrolyze GSH and GS-conjugated xenobiotics. In the cyanobacterium Nostoc, the enzyme (NsPCS) contains only the catalytic domain of the eukaryotic synthase and can act as a GSH hydrolase and weakly as a peptide ligase. The crystal structure of NsPCS in its native form solved at a 2.0-A resolution shows that NsPCS is a dimer that belongs to the papain superfamily of cysteine proteases, with a conserved catalytic machinery. Moreover, the structure of the protein solved as a complex with GSH at a 1.4-A resolution reveals a gamma-glutamyl cysteine acyl-enzyme intermediate stabilized in a cavity of the protein adjacent to a second putative GSH binding site. GSH hydrolase and PCS activities of the enzyme are discussed in the light of both structures.
Département d'Ecophysiologie Végétale et de Microbiologie, Direction des Sciences du Vivant, Laboratoire de Bioénergétique Cellulaire, Commissariat á l'Energie Atomique/Cadarache, 13108 St Paul lez Durance Cedex, France.