FIG. 4.

Western blot analysis indicates that the cellular localization of native MTB48 protein is in the cytoplasm and the culture filtrate (CFP). Ten micrograms of an M. tuberculosis cytoplasm preparation, 2.5 μg each of cell membrane, cell wall, and CFPs, and 25 ng of recombinant MTB48 were separated by SDS-PAGE, transferred to nitrocellulose, and probed with an MTB48 rabbit polyclonal antibody. A 55-kDa band (top arrow) is seen in both the cytoplasm and the recombinant protein lanes, while a 43-kDa band (middle arrow) is seen in both the cytoplasm and the CFP lanes. A second band of reactivity at approximately 38 kDa is shown in the recombinant protein lane (bottom arrow).