Inositol polyphosphate-mediated iron transport in Pseudomonas aeruginosa.
It has previously been shown that myo-inositol hexakisphosphate (myo-InsP6) mediates iron transport into Pseudomonas aeruginosa and overcomes iron-dependent growth inhibition. In this study, the iron transport properties of myo-inositol trisphosphate and tetrakisphosphate regio-isomers were studied. Pseudomonas aeruginosa accumulated iron (III) at similar rates whether complexed with myo-Ins(1,2,3)P3 or myo-InsP6. Iron accumulation from other compounds, notably D/L myo-Ins(1,2,4,5)P4 and another inositol trisphosphate regio-isomer, D-myo-Ins(1,4,5)P3, was dramatically increased. Iron transport profiles from myo-InsP6 into mutants lacking the outer membrane porins oprF, oprD and oprP were similar to the wild-type, indicating that these porins are not involved in the transport process. The rates of reduction of iron (III) to iron (II) complexed to any of the compounds by a Ps. aeruginosa cell lysate were similar, suggesting that a reductive mechanism is not the rate-determining step.
Hirst
P H
PH
Department of Pharmacy and Pharmacology, University of Bath, UK.
Riley
A M
AM
Mills
S J
SJ
Spiers
I D
ID
Poyner
D R
DR
Freeman
S
S
Potter
B V
BV
Smith
A W
AW
D001692:Biological Transport / Q000502:physiology; D007295:Inositol Phosphates / Q000378:metabolism*; D007501:Iron / Q000378:metabolism / Q000493:pharmacokinetics*; D007504:Iron Radioisotopes; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D018272:Porins / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000737:chemistry / Q000201:enzymology*
D007295:Inositol Phosphates; D007504:Iron Radioisotopes; D018272:Porins; D007501:Iron; D009247:NADH, NADPH Oxidoreductases; C024253:ferrisiderophore reductase