FIGURE 5.

Oxidation of Cys residues of RexT. A, purified His-RexT proteins (1 μg) incubated with 1 mm DTT (lane 1) or 1 mm H₂O₂ (lane 2) were separated by non-reducing SDS-PAGE. Lane M, molecular mass markers. B, oxidation of Cys residues of RexT was determined as follows. Proteins (1 μg) treated with 1 mm DTT were further incubated with (+) or without (−) 3 mm H₂O₂, and then free thiol groups were modified with AMS. The modified samples were separated by non-reducing SDS-PAGE. Open arrowheads indicate the shifted band of proteins modified with one, two, or three AMS molecules. Red, reduction; Ox, oxidation.