Demonstration of an iron-siderophore-binding protein in the outer membrane of Pseudomonas aeruginosa.

Outer membranes prepared from Pseudomonas aeruginosa grown in low-iron medium bind three times as much [59Fe]pyochelin as do membranes from cells grown in high-iron medium. The deletion of pyochelin reduced 59Fe binding to background levels. Autoradiographic analysis of sodium dodecyl sulfate polyacrylamide gel electrophoretograms of outer membrane preparations previously incubated with [59Fe]pyochelin revealed that the iron-siderophore complex bound to a low-molecular-weight protein of approximately 14,000.