title: Redox regulation of 3'-phosphoadenylylsulfate reductase from Escherichia coli by glutathione and glutaredoxins.
abstract: Inorganic sulfate (SO42-, S+VI) is reduced in vivo to sulfite (SO32-, S+IV) via phosphoadenylylsulfate (PAPS) reductase. Escherichia coli lacking glutathione reductase and glutaredoxins (gor-grxA-grxB-grxC-) barely grows on sulfate. We found that incubation of PAPS reductase with oxidized glutathione leads to enzyme inactivation with simultaneous formation of a mixed disulfide between glutathione and the active site Cys-239. A newly developed method based on thiol-specific fluorescent alkylation and gel electrophoresis showed that glutathionylated PAPS reductase is reduced by glutaredoxins via a monothiol mechanism. This glutathionylated species was also observed in poorly growing gor-grxA-grxB-grxC- cells expressing inactive glutaredoxin 2 (Grx2) C9S/C12S. However, it was absent in better growing cells expressing monothiol Grx2 C12S or wild type Grx2. Reversible glutathionylation may thus regulate the activity of PAPS reductase in vivo.
authors.affiliation: Medical Nobel Institute for Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Scheeles Väg 2, 17177 Stockholm, Sweden.
authors.forename: Christopher Horst
authors.initials: CH
authors.lastname: Lillig
authors.forename: Aristi
authors.initials: A
authors.lastname: Potamitou
authors.forename: Jens-Dirk
authors.initials: JD
authors.lastname: Schwenn
authors.forename: Alexios
authors.initials: A
authors.lastname: Vlamis-Gardikas
authors.forename: Arne
authors.initials: A
authors.lastname: Holmgren
mesh_terms: D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D017353:Gene Deletion; D054477:Glutaredoxins; D005978:Glutathione / Q000494:pharmacology; D019803:Glutathione Disulfide / Q000494:pharmacology; D007700:Kinetics; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry; D011506:Proteins / Q000235:genetics*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014357:Trypsin
chemical_list: D054477:Glutaredoxins; D010446:Peptide Fragments; D011506:Proteins; D010088:Oxidoreductases; C052449:3'-phosphoadenylyl-5'-phosphosulfate reductase; D014357:Trypsin; D005978:Glutathione; D019803:Glutathione Disulfide