Structural and functional features of the Escherichia coli hydroperoxide resistance protein OsmC.
The osmotically inducible protein OsmC, like its better-characterized homolog, the organic hydroperoxide protein Ohr, is involved in defense against oxidative stress caused by exposure to organic hydroperoxides. The crystal structure of Escherichia coli OsmC reported here reveals that the protein is a tightly folded domain-swapped dimer with two active sites located at the monomer interface on opposite sides of the molecule. We demonstrate that OsmC preferentially metabolizes organic hydroperoxides over inorganic hydrogen peroxide. On the basis of structural and enzymatic similarities, we propose that the OsmC catalytic mechanism is analogous to that of the Ohr proteins and of the structurally unrelated peroxiredoxins, directly using highly reactive cysteine thiol groups to elicit hydroperoxide reduction.
Lesniak
Jacob
J
Joan and Sanford I. Weill Graduate School of Medical Sciences of Cornell University, New York, New York 10021, USA.
Barton
William A
WA
Nikolov
Dimitar B
DB
D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
D029968:Escherichia coli Proteins; C099394:osmC protein, E coli; D006861:Hydrogen Peroxide