Acquisition of iron from citrate by Pseudomonas aeruginosa.
Transport of [14C]citrate, ferric [14C]citrate and [55Fe]ferric citrate into Pseudomonas aeruginosa grown in synthetic media containing citrate, succinate, or succinate and citrate as carbon and energy sources was measured. Cells grown in citrate-containing medium transported radiolabelled citrate and iron, whereas the succinate-grown cells transported iron but not citrate. Binding studies revealed that isolated outer and inner membranes of citrate-grown cells contain a citrate receptor, absent from membranes of succinate-grown cells. [55Fe]Ferric citrate bound to the isolated outer membranes of each cell type. The failure of citrate to compete with this binding suggests the presence of a ferric citrate receptor on the outer membranes of each cell type. Citrate induced the synthesis of two outer-membrane proteins of 41 and 19 kDa. A third protein of 17 kDa was more dominant in citrate-grown cells than in succinate-grown cells.
Harding
R A
RA
Biology Department, George Mason University, Fairfax, VA 22030-4444.
Royt
P W
PW
D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D002951:Citrates / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D007501:Iron / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000254:growth & development / Q000378:metabolism*
D001425:Bacterial Outer Membrane Proteins; D002951:Citrates; D007501:Iron