FIG. 1.

SDS-PAGE of FepB chromatography on Sephacryl S100. Periplasmic fluid containing overexpressed FepB was subjected to ammonium sulfate precipitation and anion-exchange (DE-52 column) chromatography. The purest fractions were consolidated, concentrated by ammonium sulfate precipitation, and chromatographed over Sephacryl S-100. Lanes 1, molecular mass markers (arrows), consisting of phosphorylase b (94 kDa), carbonic anhydrase (29 kDa), and lysozyme (14 kDa); 2, starting material; 3 to 21, fractions from S-100. The purest fractions (lanes 15 to 20) were collected, pooled, and used for binding experiments and animal immunizations.