6iu0 | pdb_00006iu0
Peroxiredoxin from Thermococcus kodakaraensis (0Cys mutant)
Structural highlights
Function[TDXH_THEKO] Thiol-specific peroxidase that catalyzes the reduction of hydrogen peroxide and organic hydroperoxides to water and alcohols, respectively. Plays a role in cell protection against oxidative stress by detoxifying peroxides. Publication Abstract from PubMedPeroxiredoxins from Pyrococcus horikoshii (PhPrx) and Thermococcus kodakaraensis (TkPrx) are highly homologous proteins sharing 196 of the 216 residues. We previously reported a pentagonal ring-type decameric structure of PhPrx. Here, we present the crystal structure of TkPrx. Despite their homology, unlike PhPrx, the quaternary structure of TkPrx was found to be a dodecamer comprised of six homodimers arranged in a hexagonal ring-type assembly. The possibility of the redox-dependent conversion of the molecular assembly, which had been observed in PhPrx, was excluded for TkPrx based on the crystal structure of a mutant in which all of the cysteine residues were substituted with serine. The monomer structures of the dodecameric TkPrx and decameric PhPrx coincided well, but there was a slight difference in the relative orientation of the two domains. Molecular assembly of PhPrx and TkPrx in solution evaluated by gel-filtration chromatography was consistent with the crystallographic results. For both PhPrx and TkPrx, the gel-filtration elution volume slightly increased with a decrease in the protein concentration, suggesting the existence of an equilibrium state between the decameric/dodecameric ring and lower-order assembly. This structural assembly difference between highly homologous Prxs suggests a significant influence of quaternary structure on function, worthy of further exploration. Distinct molecular assembly of homologous peroxiredoxins from Pyrococcus horikoshii and Thermococcus kodakaraensis.,Himiyama T, Oshima M, Uegaki K, Nakamura T J Biochem. 2019 Feb 22. pii: 5362029. doi: 10.1093/jb/mvz013. PMID:30796432[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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