FIG. 1.

In vivo labeling with mBBr of proteins of aerobically and anaerobically grown E. coli CAG627(pMW32). Detection of bound mBBr by fluorescence (A) and FNR by immunostaining (B). The bacteria were grown aerobically (lanes 1 and 2) or anaerobically (lanes 4 and 5) to an OD₅₇₈ of 0.7 under fnr-inducing (+) (1 mM IPTG; lanes 2 and 5) or noninducing (−) (lanes 1 and 4) conditions. Lane 3 contains 1.2 μg purified FNR. Cells were incubated for 5 min with 2 mM mBBr. Sedimented bacteria were resuspended and lysed in SDS-PAGE sample buffer (approximately 30 μg/lane); samples were subjected to SDS-PAGE and blotted onto nitrocellulose. (A) Fluorescence was measured using a Kodak ImageStation CF440 with emission at 400 to 500 nm. (B) The same blot was used subsequently for immunostaining with anti-FNR. Staining was recorded as the absorbance at 400 to 500 nm. The positions of proteins corresponding to M_r 30,000 to M_r 90,000 (calculated from M_r markers) are shown to the left of the blots.