Fig 4.

Protein localization studies show that ChtA, ChtB, ChtC, and CirA are associated predominately with the membrane fraction in C. diphtheriae 1737. Cultures were grown in mPGT medium under low-Fe (0.5 μM) conditions and bacteria were fractionated as described in Materials and Methods. Polyclonal antiserum specific to the proteins indicated was used for detection of total cellular proteins (T), soluble cytosolic proteins (S), and membrane-associated proteins (M). Samples were loaded using equivalent protein levels.