Sulfur metabolism under stress:Oxidized glutathione inhibits methionine biosynthesis by destabilizing the enzyme cystathionineγ-synthase  

作　　者：Yael Hacham Alex Kaplan Elad Cohen Maayan Gal Rachel Amir 

机构地区：[1]Laboratory of Plant Science,Migal,Galilee Research Institute,Kiryat Shmona 11016,Israel [2]Tel-Hai College,Upper Galilee 11016,Israel [3]Department of Oral Biology,Goldschleger School of Dental Medicine,Faculty of Medicine,Tel Aviv University,Tel Aviv 6997801,Israel

出　　处：《Journal of Integrative Plant Biology》2025年第1期87-100,共14页植物学报(英文版)

基　　金：supported by the Israel Science Foundation(ISF Grant no.1857/20);Binational Agricultural Research&Development(BARD Grant no.IS-4248-09 R)。

摘　　要：Cysteine is the precursor for the biosynthesis of glutathione,a key stress-protective metabolite,and methionine,which is imperative for cell growth and protein synthesis.The exact mechanism that governs the routing of cysteine toward glutathione or methionine during stresses remains unclear.Our study reveals that under oxidative stress,methionine and glutathione compete for cysteine and that the increased oxidized glutathione(GSSG)levels under stress hinder methionine biosynthesis.Moreover,we find that inhibition occurs as GSSG binds to and accelerates the degradation of cystathionineγ-synthase,a key enzyme in the methionine synthesis pathway.Consequently,this leads to a reduction in the flux toward methionine-derived metabolites and redirects cysteine utilization toward glutathione,thereby enhancing plant protection.Our study suggests a novel regulatory feedback loop involving glutathione,methionine,and cysteine,shedding light on the plant stress response and the adaptive rerouting of cysteine.These findings offer new insights into the intricate balance of growth and protection in plants and its impact on their nutritional value due to low methionine levels under stress.

关 键 词：cystathionineγ-synthase(CGS) CYSTEINE GLUTATHIONE metabolic competition METHIONINE oxidative stress sulfur metabolism TOBACCO 

分 类 号：O62[理学—有机化学]