Figure 1

Secretion of ESAT6 fused to the passenger of Hbp. (A) Schematic representation of secretion and display strategy based on the Hbp passenger and β-domain crystal structures[9, 44]. ESAT6[45] is fused to the Hbp passenger domain by replacing any of the side domains d1 (red), d2 (green), d3 (yellow), d4 (magenta) or d5 (orange). Scissors indicate a cleavage site between the passenger and β-domain, which was left intact (+) for secretion purposes and disrupted (-) for surface display. The image was created using MacPyMol. (B C) Hbp constructs were expressed in E. coli MC1061 and the equivalent of 0.03 OD₆₆₀ units cells (c) and corresponding culture medium (m) samples was analyzed by SDS-PAGE and Coomassie staining. (B) Expression and secretion of Hbp constructs compared to the empty vector control (EV). (C) Secretion of Hbp constructs carrying ESAT6. (D) Samples described under C were analyzed by immunoblotting using ESAT6 specific antibodies. Cleaved Hbp passenger (>) and ~ 28 kDa β-domain[19] (β) are indicated. Molecular mass (kDa) markers are shown at the left side of the panels.