Structural and biochemical analysis of a type II free methionine-R- sulfoxide reductase from Thermoplasma acidophilum

Hyun Sook Kim, Geun Hee Kwak, Kitaik Lee, Chang Hwa Jo, Kwang Yeon Hwang, Hwa Young Kim

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Free methionine-R-sulfoxide reductase (fRMsr) enzymes only reduce the free form of methionine-R-sulfoxide and can be grouped into two types with respect to the number of conserved Cys residues in the active sites. In this work, the crystal structures of type II fRMsr from Thermoplasma acidophilum (TafRMsr), which contains two conserved Cys, have been determined in native form and in a complex with the substrate. The overall structure of TafRMsr consists of a central β-sheet encompassed by a two-α-helix bundle flanking on one side and one small α-helix on the other side. Based on biochemical and growth complementation assays, Cys84 is demonstrated to be the catalytic Cys. The data also show that TafRMsr functions as an antioxidant protein. Structural analyses reveal insights into substrate recognition and orientation, conformational changes in the active site during substrate binding, and the role of active site residues in substrate binding. A model for the catalytic mechanism of type II TafRMsr is suggested, in which intramolecular disulfide bond formation is not involved. In addition, the biochemical, enzymatic, and structural properties of type II TafRMsr are compared with those of type I enzymes.

Original languageEnglish
Pages (from-to)10-19
Number of pages10
JournalArchives of Biochemistry and Biophysics
Publication statusPublished - 2014 Oct 15

Bibliographical note

Funding Information:
We thank the staff of beamline 5C-SBII at the Pohang Light Source (Korea) for technical support, the staff at the Korea Basic Science Institute (KBSI, Daejeon, Korea) for the use of a mosquito crystallization robot, and the members at beamline BL-17A of the Photon Factory for their assistance with data collection (2012G189; Tsukuba, Japan). This work was supported by grants from the National Research Foundation of Korea ( 2011-0028166 and 2013R1A1A2008404 ).


  • Catalysis
  • Methionine sulfoxide reductase
  • ROS
  • Resolving Cys
  • Thermoplasma
  • fRMsr

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology


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