Nature structural biology
5, 400 - 406 (1998)
doi:10.1038/nsb0598-400
Crystal structure of a novel human peroxidase enzyme at 2.0 Å resolutionHee-Jeong Choi1, 3, Sang Won Kang2, Chul-Hak Yang3, Sue Goo Rhee2
& Seong-Eon Ryu1, 4
1Division of Protein Engineering, Korea Research Institute of Bioscience and Biotechnology, KIST, P.O.Box 115, Yusong,Taejon 305-600, South Korea.
2Laboratory of Cell Signaling, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
3Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-742, South Korea.
4email: ryuse@mcr1.kribb.re.kr Hydrogen peroxide (H2O2) has been implicated recently as an intracellular messenger that affects cellular processes including protein phosphorylation, transcription and apoptosis. A set of novel peroxidases, named peroxiredoxins (Prx), regulate the intracellular concentration of H2O2 by reducing it in the presence of an appropriate electron donor. The crystal structure of a human Prx enzyme, HORF6, reveals that the protein contains two discrete domains and forms a dimer. The N-terminal domain has a thioredoxin fold and the C-terminal domain is used for dimerization. The active site cysteine (Cys 47), which exists as cysteine-sulfenic acid in the crystal, is located at the bottom of a relatively narrow pocket. The positively charged environment surrounding Cys 47 accounts for the peroxidase activity of the enzyme, which contains no redox cofactors.
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