FIG. 2.

Levels of the mature and the precursor forms of FlgI in the ΔflgI strain producing Cys-eliminated FlgI. The FlgI proteins from RP437 and YZ1 cells harboring pBAD24 (vector), pYZ201 (wild-type FlgI), or the derivatives of pYZ201 (C254A, C338A, and C254A/C338A substitutions) were detected by immunoblotting using anti-FlgI antibodies. Whole-cell extracts were prepared by TCA precipitation. (A) The position of FlgI is indicated on the right side of the figure. Ara, l-arabinose. (B) A culture in the exponential growth phase was supplemented with l-arabinose and incubated for 10 min. Then the aliquot was incubated for another 10 min in the absence or presence of 2 mM NaN₃. The positions of the precursor (38-kDa band) and the mature (36-kDa band) forms of FlgI are indicated on the right side of the figure. Whereas the levels of the mature forms of the Cys-eliminated FlgI derivatives were lower than that of wild-type FlgI, those of the precursor forms were unchanged.