FIG 1.

HupB is not expressed by M. tuberculosis ΔhupB mutant but is constitutively expressed in the hupB-complemented strain. Fifty-μg total protein samples of the whole-cell sonicates of M. tuberculosis H37Rv and the M. tuberculosis ΔhupB mutant grown under high-iron (HI; 8 μg Fe ml⁻¹) and low-iron (LI; 0.02 μg Fe ml⁻¹) conditions were separated electrophoretically by SDS-PAGE (A), transferred onto nitrocellulose membrane, and developed with rabbit anti-HupB antibodies diluted 1:2,500 (B). (C) Immunoblot showing the constitutive expression of HupB in M. tuberculosis ΔhupB/pMS101 in both HI and LI organisms (mutant strain is shown for comparison). The arrow indicates HupB, and M is the molecular size marker.