FIG. 3.

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of polypeptides affinity isolated from total membranes of H. somnus strain 649 grown under iron-restricted conditions in the presence of bovine Tf. The polypeptides were isolated using biotinylated bovine (lane 1), goat (lane 2), and ovine (lane 3) Tfs as binding ligands. Lane 4 represents a control sample obtained when the affinity isolation procedure was performed in the absence of biotinylated Tf. The numbers refer to the sizes and positions of protein standards.