title: Irreversible oxidation of the active-site cysteine of peroxiredoxin to cysteine sulfonic acid for enhanced molecular chaperone activity.
abstract: The thiol (-SH) of the active cysteine residue in peroxiredoxin (Prx) is known to be reversibly hyperoxidized to cysteine sulfinic acid (-SO(2)H), which can be reduced back to thiol by sulfiredoxin/sestrin. However, hyperoxidized Prx of an irreversible nature has not been reported yet. Using an antibody developed against the sulfonylated (-SO(3)H) yeast Prx (Tsa1p) active-site peptide (AFTFVCPTEI), we observed an increase in the immunoblot intensity in proportion to the H(2)O(2) concentrations administered to the yeast cells. We identified two species of hyperoxidized Tsa1p: one can be reduced back (reversible) with sulfiredoxin, and the other cannot (irreversible). Irreversibly hyperoxidized Tsa1p was identified as containing the active-site cysteine sulfonic acid (Tsa1p-SO(3)H) by mass spectrometry. Tsa1p-SO(3)H was not an autoxidation product of Tsa1p-SO(2)H and was maintained in yeast cells even after two doubling cycles. Tsa1p-SO(3)H self-assembled into a ring-shaped multimeric form was shown by electron microscopy. Although the Tsa1p-SO(3)H multimer lost its peroxidase activity, it gained approximately 4-fold higher chaperone activity compared with Tsa1p-SH. In this study, we identify an irreversibly hyperoxidized Prx, Tsa1p-SO(3)H, with enhanced molecular chaperone activity and suggest that Tsa1p-SO(3)H is a marker of cumulative oxidative stress in cells.
authors: Department of Biological Sciences, Chonnam National University, Gwangju 500-757, Korea.
authors: Jung Chae
authors: JC
authors: Lim
authors: Hoon-In
authors: HI
authors: Choi
authors: Yu Sun
authors: YS
authors: Park
authors: Hyung Wook
authors: HW
authors: Nam
authors: Hyun Ae
authors: HA
authors: Woo
authors: Ki-Sun
authors: KS
authors: Kwon
authors: Yu Sam
authors: YS
authors: Kim
authors: Sue Goo
authors: SG
authors: Rhee
authors: Kanghwa
authors: K
authors: Kim
authors: Ho Zoon
authors: HZ
authors: Chae
mesh_terms: D020134:Catalytic Domain; D003545:Cysteine / Q000031:analogs & derivatives* / Q000737:chemistry*; D015180:Electrophoresis, Gel, Two-Dimensional; D015966:Gene Expression Regulation, Fungal; D006861:Hydrogen Peroxide / Q000737:chemistry; D008854:Microscopy, Electron; D008954:Models, Biological; D018832:Molecular Chaperones / Q000737:chemistry*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010100:Oxygen / Q000737:chemistry*; D010544:Peroxidases / Q000737:chemistry / Q000502:physiology*; D054464:Peroxiredoxins / Q000737:chemistry / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000502:physiology*
chemical_list: D018832:Molecular Chaperones; D029701:Saccharomyces cerevisiae Proteins; D006861:Hydrogen Peroxide; D010544:Peroxidases; C496253:Tsa1 protein, S cerevisiae; D054464:Peroxiredoxins; D003545:Cysteine; D010100:Oxygen; C013461:cysteine sulfinic acid