Abstract
Methionine sulfoxide reductase A (MsrA) reduces free and protein-based methionine-S-sulfoxide to methionine. Structures of 1-Cys MsrAs lacking a resolving Cys, which interacts with catalytic Cys, are unknown. In addition, no structural information on selenocysteine (Sec)-containing MsrA enzymes has been reported. In this work, we determined the crystal structures of 1-Cys type selenoprotein MsrA from Clostridium oremlandii at 1.6-1.8 Å, including the reduced, oxidized (sulfenic acid), and substrate-bound forms. The overall structure of Clostridium MsrA, consisting of ten α-helices and six β-strands, folds into a catalytic domain and a novel helical domain absent from other known MsrA structures. The helical domain, containing five helices, tightly interacts with the catalytic domain, and is likely critical for catalytic activity due to its association with organizing the active site. This helical domain is also conserved in several selenoprotein MsrAs. Our structural analysis reveals that the side chain length of Glu55 is critical for the proton donor function of this residue. Our structures also provide insights into the architecture of the 1-Cys MsrA active site and the roles of active site residues in substrate recognition and catalysis.
Original language | English |
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Pages (from-to) | 1-8 |
Number of pages | 8 |
Journal | Archives of Biochemistry and Biophysics |
Volume | 545 |
DOIs | |
Publication status | Published - 2014 Mar 1 |
Bibliographical note
Funding Information:We thank the staff of beamlines 4A at the Pohang Accelerator Laboratory and BL1A at the Photon Factory for technical support. We are also grateful to the staff at the Korea Basic Science Institute (Daejeon, Korea) for the use of a mosquito crystallization robot and the Rigaku MicroMax-007HF X-ray generator. This work was supported by grants from the National Research Foundation of Korea (2011-0028166 and 2013-044795).
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
Keywords
- Catalysis
- Clostridium
- Methionine sulfoxide reductase
- MsrA
- Selenocysteine
- Selenoprotein
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology