FIG. 1.

(a) Western blot analysis of CheX expression in wild-type, cheX mutant, and cheX⁺ cells. Cell lysates from wild-type, cheX mutant, and cheX⁺ cells were analyzed by SDS-PAGE and Western blotting with anti-CheX antiserum (top panel). The overexpression of CheX in the cheX⁺ strain was likely due to the strong flgB promoter and multicopy nature of the shuttle vector used. As an internal control, 2 μg of each cell lysate was probed with anti-DnaK antibodies (bottom panel). (b) Western blot analysis of CheY3, CheA2, FlaB, and FlaA expression in wild-type and cheX mutant cells. Cell lysates (2 μg for FlaB) from wild-type and cheX mutant cells were probed with antibodies specific for CheY3, CheA2, FlaB, and FlaA.