Vacuolar sequestration of glutathione S-conjugates outcompetes a possible degradation of the glutathione moiety by phytochelatin synthase

• Verfasst von: Grzam, Anke [VerfasserIn]
• Verfasst von: Tennstedt, Pierre [VerfasserIn]
• Verfasst von: Clemens, Stephan [VerfasserIn]
• Verfasst von: Hell, Rüdiger [VerfasserIn]
• Verfasst von: Meyer, Andreas [VerfasserIn]
• Titel: Vacuolar sequestration of glutathione S-conjugates outcompetes a possible degradation of the glutathione moiety by phytochelatin synthase
• Verf.angabe: Anke Grzam, Pierre Tennstedt, Stephan Clemens, Rudiger Hell, Andreas J. Meyer
• Umfang: 7 S.
• Fussnoten: Gesehen am 15.05.2017
• Titel Quelle: Enthalten in: Federation of European Biochemical Societies: FEBS letters
• Jahr Quelle: 2006
• Band/Heft Quelle: 580(2006), 27, S. 6384-6390
• ISSN Quelle: 1873-3468
• DOI: doi:10.1016/j.febslet.2006.10.050
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1558587144

Abstract

Monochlorobimane was used as a model xenobiotic for Arabidopsis to directly monitor the compartmentation of glutathione-bimane conjugates in situ and to quantify degradation intermediates in vitro. Vacuolar sequestration of the conjugate was very fast and outcompeted carboxypeptidation to the γ-glutamylcysteine-bimane intermediate (γ-EC-B) by phytochelatin synthase (PCS) in the cytosol. Following vacuolar sequestration, degradation proceeded to cysteine-bimane without intermediate. Only co-infiltration of monochlorobimane with Cd2+ and Cu2+ increased γ-EC-B formation to 4% and 25%, respectively, within 60 min. The role of PCS under simultaneous heavy metal stress was confirmed by investigation of different pcs1 null-mutants. In the absence of elevated heavy metal concentrations glutathione-conjugates are therefore first sequestered to the vacuole and subsequently degraded with the initial breakdown step being rate-limiting.