FIG. 2.

Specific fluorescence of mBBr-labeled FNR in aerobically and anaerobically grown E. coli CAG627(pMW32). The specific fluorescence was calibrated using purified FNR with one, two, three, and five Cys thiols/FNR (small solid diamonds) labeled with mBBr. After separation by SDS-PAGE and blotting onto nitrocellulose, mBBr fluorescence (integrated pixel intensity of fluorescence [PI_fluor]) and FNR immunostaining (integrated pixel intensity of immunostaining [PI_immuno]) were measured by fluorescence and absorption imaging as described in the legend to Fig. 1. The specific labeling of the different FNR species (PI_fluor/PI_immuno) was determined as described in footnote a of Table 1, and the specific labeling of FNR with five accessible Cys residues was taken as 100%. Following the same method, the PI_fluor/PI_immuno of protein from aerobically grown cells (one solid circle) and anaerobically grown cells (one solid square) was determined. The mean experimental values are derived from four or more independent experiments, and the standard deviations (error bars) are given.