FIG. 2.

Western blot analysis of fiber-derived CsgA from whole cells grown at 28 and 37°C. The cell pellets were immediately resuspended in SDS sample buffer (−) or treated with formic acid (+) as described in Materials and Methods. Minor signals for the fiber subunit which could vary in their intensities were regularly found in the slot (s) and in the gel corresponding to a dimer (d), while the major signal was consistent with the running behavior of a monomer (m). SR-11 and ATCC 14024-1s showed a signal for CsgA only at 28°C and not at 37°C. csgA knockouts did not show any signal at all. Lanes: 1, SR-11; 2, MAE2; 3, ATCC 14028-1s; 4, MAE1.