title: S-sulfocysteine synthase function in sensing chloroplast redox status.
abstract: The minor chloroplastic O-acetylserine(thiol)lyase isoform encoded by the CS26 gene in Arabidopsis thaliana has been described as an S-sulfocysteine synthase enzyme that plays an important role in chloroplast function. This enzyme is located in the thylakoid lumen, and its S-sulfocysteine activity is essential for the proper photosynthetic performance of the chloroplast under long-day growth conditions. Based on the present knowledge of this enzyme, we suggest that S-sulfocysteine synthase functions as a protein sensor to detect the accumulation of thiosulfate as a result of the inadequate detoxification of reactive oxygen species generated under conditions of excess light to produce the S-sulfocysteine molecule that triggers protection mechanisms of the photosynthetic apparatus.
authors: Instituto de Bioquímica Vegetal y Fotosíntesis; Consejo Superior de Investigaciones Científicas and Universidad de Sevilla; Sevilla, Spain.
authors: Cecilia
authors: C
authors: Gotor
authors: Luis C
authors: LC
authors: Romero
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D019757:Carbon-Oxygen Lyases / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism*; D003545:Cysteine / Q000031:analogs & derivatives* / Q000378:metabolism; D017343:Genes, Plant; D008027:Light; D008190:Lyases / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D017440:Photoperiod; D010788:Photosynthesis; D020033:Protein Isoforms; D017382:Reactive Oxygen Species / Q000378:metabolism; D013885:Thiosulfates / Q000378:metabolism*; D020524:Thylakoids / Q000201:enzymology
chemical_list: D029681:Arabidopsis Proteins; D020033:Protein Isoforms; D017382:Reactive Oxygen Species; D013885:Thiosulfates; C011119:S-sulphocysteine; C018725:O-acetylhomoserine (thiol)-lyase; D008190:Lyases; C022706:S-sulfocysteine synthase; D019757:Carbon-Oxygen Lyases; D003545:Cysteine
keywords: Arabidopsis; S-sulfocysteine; cysteine; redox regulation; sulfur metabolism