FIG. 4.
EsxB produced in trans is secreted with or without a C-terminal histidine tag. Wild-type or esxB mutant bacilli with no vector, vector carrying esxB (esxB/EsxB+) or a modified esxB with six histidine residues (esxB/EsxB-His) were grown to the same optical density (A600 nm of 3) in LB medium with 0.5% glucose (LBG). Cells cultures (Total) or an equivalent volume of culture supernatant (Sup) were precipitated with TCA, separated by SDS-PAGE, and detected by immunoblotting with specific antibodies (anti-EsxB, anti-His, and anti-L6 as a loading control). Extracts from cells carrying plasmids expressing esxB were diluted 10 times compared to extracts from wild-type and esxB mutant strains. α, anti; WT, wild type.