FIG. 3.

SDS electrophoresis, in 12% gel, of the protein fractions obtained by affinity chromatography on a column with glutathione Sepharose. Proteins were isolated from E. coli TG-1 containing pGEX-LuxRΔN (lane 1), pGEX-LuxR (lane 2), or pGEX-LuxRΔC (lane 3). The bands of glycerol kinase (56.2 kDa; lanes 1 and 3) and of elongation factor EF-Tu (43.3 kDa; lanes 1 and 2) are present also (according to mass-spectrometry analysis, these bands correspond to the glycerol kinase and EF-Tu). These proteins accompanied the GST protein purified using gentle washing conditions.