FIG. 4.
Effect of ferrous iron concentration on the synthesis of some proteins in A. ferrooxidans grown on elemental sulfur. Cells were grown on elemental sulfur medium, to which the indicated ferrous iron concentrations and [35S]methionine were added. After 30 h of incubation under these conditions, total-cell proteins were separated by 2-D PAGE (left) and subjected to autoradiography, and the intensities of the indicated spots were determined by using an image analysis program (graph on the right). The positions of the indicated spots were identified previously by their coordinates in the 2-D gels and by N-terminal amino acid sequence analysis of the isolated spots.