Differential Contributions of the Outer Membrane Receptors PhuR and HasR to Heme Acquisition in Pseudomonas aeruginosa

作者：Smith Aaron D; Wilks Angela^*

来源：JOURNAL OF BIOLOGICAL CHEMISTRY, 2015, 290(12): 7756-7766.

DOI：10.1074/jbc.M114.633495

• Cell Surface Receptor
• Heme
• Iron Metabolism
• Mass Spectrometry (MS)
• Membrane Transport

Background:Pseudomonas aeruginosa utilizes extracellular heme as a source of iron on infection of the host. Results: Both PhuR and HasR are required for efficient utilization of heme by P. aeruginosa. Conclusion: Non-redundant outer membrane receptors allow for heme acquisition across a range of physiological conditions. Significance: PhuR and HasR have complimentary roles in heme acquisition and utilization. Pseudomonas aeruginosa PAO1 encodes two outer membrane receptors, PhuR (Pseudomonasheme uptake) and HasR (heme assimilation system). The HasR and PhuR receptors have distinct heme coordinating ligands and substrate specificities. HasR is encoded in an operon with a secreted hemophore, HasAp. In contrast the non-hemophore-dependent PhuR is encoded within an operon along with proteins required for heme translocation into the cytoplasm. Herein we report on the contributions of the HasR and PhuR receptors to heme uptake and utilization. Employing bacterial genetics and isotopic [C-13]heme labeling studies we have shown both PhuR and HasR are required for optimal heme utilization. However, the unique His-Tyr-ligated PhuR plays a major role in the acquisition of heme. In contrast the HasR receptor plays a primary role in the sensing of extracellular heme and a supplementary role in heme uptake. We propose PhuR and HasR represent non-redundant heme receptors, capable of accessing heme across a wide range of physiological conditions on colonization of the host.

• 出版日期2015-3-20