1. Cg-OxyR shows rapid conformational changes upon oxidation.
Cg-OxyR shows rapid conformational changes upon oxidation. (A) Structural view of the tryptophan location and its side-chain flip upon oxidation. (B) The side-chain flip leads to a decrease in intrinsic fluorescence. Fluorescence spectroscopy of Cg-OxyR upon oxidation by H2O2 and rereduction by DTT. (C) Cg-OxyR requires both cysteines for the full conformational change. One micromolar WT and C206S/C215S variants were mixed with 5 μM H2O2, and fluorescence decrease was monitored over time in a stopped-flow mixing device. (D) The conformational change rate increases with H2O2 concentration in a hyperbolic manner. Increasing concentrations of H2O2 were added to Cg-OxyR. The progress curves were fitted to single exponential equation, and the observed rate constants plotted against the H2O2 concentration (n = 3). Inset shows the progress curves of Cg-OxyR fluorescence changes upon addition of 10, 20, or 30 μM H2O2.
Brandán Pedre et al. PNAS doi: /pnas
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