FIG. 2.

SDS-PAGE analysis of wild-type B. bronchiseptica B013N and mutant derivative BRM10. Strain B013N, streptonigrin-resistant mutant BRM10 harboring the plasmid vector pRK415, and the complementing 1.6-kb B. pertussis KpnI-PstI DNA fragment as pP9KP were grown in parallel under iron-replete (+) and iron-depleted (−) conditions, and cell fractions were prepared as described in Materials and Methods. (A) Soluble cell fractions showing the iron-repressed ca. 59-kDa AlcC protein (arrowhead). (B) Total membrane fractions; the 79-kDa iron-repressed protein, which is absent in mutant BRM10(pRK415), migrates as the middle species of a protein triplet (arrowhead). The migration positions of molecular mass protein standards are shown on the left in kilodaltons.