We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
An efflux pump is required for siderophore recycling by Pseudomonas aeruginosa.
- Authors
Yeterian, Emilie; Martin, Lois W.; Lamont, Iain L.; Schalk, Isabelle J.
- Abstract
Summary Pyoverdine (PVDI) is a siderophore produced by Pseudomonas aeruginosa in order to obtain iron. This molecule is composed of a fluorescent chromophore linked to an octapeptide. Following secretion from the bacteria, PVDI chelates iron ions and the resulting Fe-PVDI complexes are taken up by the bacteria through a cell surface receptor protein. The iron is released in the periplasm and the resulting PVDI is recycled, being secreted out of the bacteria by a previously unknown mechanism. Three genes with the potential to encode an efflux system are adjacent to, and coregulated with, genes required for PVDI-mediated iron transport. Mutation of genes encoding this efflux pump (named PvdRT-OpmQ) prevented recycling of PVDI from the periplasm into the extracellular medium. Fluorescence microscopy showed that in the mutant bacteria PVDI accumulated in the periplasm. Gallium (Ga3+), a metal that cannot be removed from PVDI by reduction, is taken up by P. aeruginosa when chelated by PVDI. Recycling did not occur after transport of PVDI-Ga3+ and fluorescence accumulated in the periplasm even when the PvdRT-OpmQ efflux pump was functional. Cellular fractionation showed that PVDI-synthesizing bacteria lacking PvdRT-OpmQ secreted PVDI but had an approximately 20-fold increase in the amount of PVD present in the periplasm, consistent with an inability to recycle PVDI. Collectively, these data show that PvdRT-OpmQ is involved in recycling of PVDI from the periplasm to the extracellular medium and recycling requires release of the metal ion from PVDI.
- Subjects
SIDEROPHORES; PSEUDOMONAS aeruginosa; IRON ions; CELL receptors; PROTEINS; FLUORESCENCE microscopy; PERIPLASM; GALLIUM
- Publication
Environmental Microbiology Reports, 2010, Vol 2, Issue 3, p412
- ISSN
1758-2229
- Publication type
Article
- DOI
10.1111/j.1758-2229.2009.00115.x