FIGURE 5.

Reduction of Qrc with periplasmic proteins. A, reduction of Qrc with [FeFe] hydrogenase under H₂ in the absence (1) or presence of TpIc₃ (2) is shown. B, reduction of Qrc by FdhAB and formate in the absence of any cytochrome (1, dashed line) or in the presence of cytochrome c₅₅₃ (1, solid line), TpIc₃ (2), or both cytochromes (3) is shown. The arrow indicates the time of enzyme/cytochrome addition. Reduction was monitored by the increased absorption at 419 nm.