Fig 3.
(A) SDS-PAGE and subsequent pseudoperoxidase staining (heme staining) of culture supernatants of Xanthomonas sp. 35Y ΔroxA harboring chromosomally integrated roxAXsp orthologs. Each strain was grown in the absence (−) or presence (+) of the inducer l-rhamnose (0.1%). Xanthomonas sp. 35Y ΔroxA and Xanthomonas sp. 35Y ΔroxA with pNH1-roxAXsp (RoxAXsp) were used as negative and positive controls, respectively. (B) Purification of recombinant RoxA orthologs. RoxAXsp, RoxACco, and RoxAMfu were purified from rhamnose-grown cultures by chromatography of concentrated cell-free culture fluid on Q-Sepharose and hydroxyapatite, as described in Materials and Methods. Aliquots of the respective RoxA pools after the hydroxyapatite step were separated by SDS-PAGE and stained with silver. Overloading of the lanes indicates the absence of significant amounts of contaminating proteins.