5fa9

Bifunctional Methionine Sulfoxide Reductase AB (MsrAB) from Treponema denticola

spinqualitylabelsall models 5fa9, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5fa9 is a 2 chain structure with sequence from Treponema denticola ATCC 35405. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.302Å Ligands: D1D, DTT Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q73PT7_TREDE Has an important function as a repair enzyme for proteins that have been inactivated by oxidation. Catalyzes the reversible oxidation-reduction of methionine sulfoxide in proteins to methionine.[HAMAP-Rule:MF_01401] Publication Abstract from PubMed Many bacteria, particularly pathogens, possess methionine sulfoxide reductase A (MsrA) and B (MsrB) as a fusion form (MsrAB). However, it is not clear why they possess a fusion MsrAB form rather than the separate enzymes that exist in most organisms. In this study, we performed biochemical and kinetic analyses of MsrAB from Treponema denticola (TdMsrAB), single-domain forms (TdMsrA and TdMsrB), and catalytic Cys mutants (TdMsrAB(C11S) and TdMsrAB(C285S)). We found that the catalytic efficiency of both MsrA and MsrB increased after fusion of the domains and that the linker region (iloop) that connects TdMsrA and TdMsrB is required for the higher catalytic efficiency of TdMsrAB. We also determined the crystal structure of TdMsrAB at 2.3 A, showing that the iloop mainly interacts with TdMsrB via hydrogen bonds. Further kinetic analysis using the iloop mutants revealed that the iloop-TdMsrB interactions are critical to MsrB and MsrA activities. We also report the structure in which an oxidized form of dithiothreitol, an in vitro reductant for MsrA and MsrB, is present in the active site of TdMsrA. Collectively, the results of this study reveal an essential role of the iloop in maintaining the higher catalytic efficiency of the MsrAB fusion enzyme and provide a better understanding of why the MsrAB enzyme exists as a fused form. Essential Role of the Linker Region in the Higher Catalytic Efficiency of a Bifunctional MsrA-MsrB Fusion Protein.,Han AR, Kim MJ, Kwak GH, Son J, Hwang KY, Kim HY Biochemistry. 2016 Sep 13;55(36):5117-27. doi: 10.1021/acs.biochem.6b00544. Epub , 2016 Sep 1. PMID:27551953 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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