|Royt, Paulette - GEORGE MASON UNIVERSITY|
|Moneychuck, Robert - GEORGE MASON UNIVERSITY|
|Ravich, Vadim - GEORGE MASON UNIVERSITY|
|Ponnaluri, Padma - GEORGE MASON UNIVERSITY|
|Pannell, Lewis - NAT INSTITUTE OF HEALTH|
|Chandhoke, Vikas - GEORGE MASON UNIVERSITY|
|Stalick, Wayne - GEORGE MASON UNIVERSITY|
|DE Sesso, Leo - GEORGE MASON UNIVERSITY|
|Ghei, Rashmi - GEORGE MASON UNIVERSITY|
Submitted to: Journal of Bacteriology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 25, 2001
Publication Date: December 1, 2001
Citation: ROYT, P.W., MONEYCHUCK, R.V., RAVICH, V., PONNALURI, P., PANNELL, L.K., BUYER, J.S., CHANDHOKE, V., STALICK, W.M., DE SESSO, L.C., GHEI, R. 4-HYDROXY-2-NONYLQUINDINE: A NOVEL IRON CHELATOR ISOLATED FROM A BACTERIAL CELL MEMBRANE. JOURNAL OF BACTERIOLOGY. 29: 387-397. 2001. Interpretive Summary: Siderophores are iron-binding compounds produced by most bacteria and fungi. Siderophores are produced when the cell is starved for iron. The siderophores are released to the extracellular environment. The siderophore then binds iron and the ferric siderophore is actively transported back in to the cell, where the iron is released and used by the microorganism. Siderophores have been shown to have antibacterial and antifungal properties, and siderophores are virulence factors in certain animal pathogens. A study of iron transport and metabolism in the human pathogen Pseudomonas aeruginosa revealed that the cytoplasmic membrane was red in iron-rich cells, suggesting that the membrane was high in iron. In this study the molecule that binds iron in the membrane was identified as 4-hydroxy-2-nonylquinoline, a compound known to have antibiotic activity. While the purpose of storing iron in the cytoplasmic membrane is not yet clear, it might be useful for iron storage before incorporation into bacterioferritin or cytochromes. Alternatively, extracellular iron from siderophores might be transferred into cytoplasmic 4-hydroxy-2-nonylquinoline during the transport process. This study will be useful to scientists studying microbial iron transport and physiology, and may eventually lead to novel strategies for suppressing the growth of pathogens.
Technical Abstract: The membrane associated iron chelator of Pseudomonas aeruginosa has been extracted from membranes of iron-rich cells with ethanol, and purified by phase HPLC. Using 13C NMR and FAB mass spectroscopy, the structure of the chelator has been determined to be 4-hydroxy-2-nonyl quinoline. This compound has been previously isolated and named pseudan IX, a name which we use here. We synthesized pseudan IX and show that the spectral properties of the synthesized compound and the purified compounds are nearly identical. Also purified from the ethanol exract of membranes is 4-hydroxy-2-heptylquinoline, i.e. pseudan VII. Bacterially purified pseudan IX binds iron as indicated by the incorporation of radiolabeled iron into the chelator and by the formation of pink micelles in the ethanol extract. The formation of pink micelles upon addition of iron to the synthesized compound indicates that it binds iron.