FIG. 3.
Flotation sucrose gradient analysis of multimers of PulD and PulD-mCherry in the presence of chromosomal (PulS) or plasmid levels of PulS (PulS+++). pulD and pulD-mCherry were expressed from the chromosome at the λatt site without IPTG induction in PAP9124 (lane 1) and PAP9138 (lanes 2 to 4), respectively. Induction of the pul operon was obtained with 0.4% maltose in PAP9138 (lane 5). PulD-mCherry was analyzed in the presence of elevated PulS levels in PAP9138 (containing pCHAP580; lanes 6 to 8). Proteins in samples collected from the gradients were dissolved in SDS and examined by SDS-PAGE and immunoblotting with anti-PulD, anti-RFP, anti-OmpA, and anti-PulS antibodies.