| Structural highlights
6nlg is a 4 chain structure with sequence from Pseudomonas aeruginosa PAO1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Method: | X-ray diffraction, Resolution 1.5Å |
| Ligands: | , , , , |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
BFRB_PSEAE The major iron-storage protein, part of the heterooligomeric bacterioferritin (BFR) complex. The ferroxidase center binds Fe(2+), oxidizes it using dioxygen to Fe(3+), and participates in the subsequent Fe(3+) oxide mineral core formation within the central cavity of the BFR protein shell. Can store up to 600 iron atoms per bacterioferritin protein molecule (PubMed:19575528, PubMed:20067302, PubMed:25640193, PubMed:26368531). In iron-sufficient conditions (10 uM Fe(2+)) iron accumulates in BFR until about 12 hours, when it starts to deplete; stored iron is no longer detectable by 24 hours growth, iron is mobilized from the BFR as levels drop in the growth media (PubMed:28318006). Iron release from the BFR requires ferredoxin NADP reductase (FPR) and bacterioferritin-associated ferredoxin (Bfd) (PubMed:19575528, PubMed:22812654, PubMed:26368531). Reduction of the BfrB heme group occurs in the presence of Bfd, strongly suggesting that the BfrB-Bfd complex allows heme to mediate electron transfer from FPR to the Fe(3+) iron core in the BFR shell prior to its release as Fe(2+) (PubMed:19575528, PubMed:22812654, PubMed:26368531).[1] [2] [3] [4] [5] [6]
Publication Abstract from PubMed
The iron storage protein bacterioferritin (BfrB) is central to bacterial iron homeostasis. The mobilization of iron from BfrB, which requires binding by a cognate ferredoxin (Bfd), is essential to the regulation of cytosolic iron levels in P. aeruginosa. This paper describes the structure-guided development of small molecule inhibitors of the BfrB-Bfd protein-protein interaction. The process was initiated by screening a fragment library and followed by obtaining the structure of a fragment hit bound to BfrB. The structural insights were used to develop a series of 4-(benzylamino)- and 4-((3-phenylpropyl)amino)-isoindoline-1,3-dione analogs that selectively bind BfrB at the Bfd binding site. Challenging P. aeruginosa cells with the 4-substituted isoindoline analogs revealed a dose-dependent growth phenotype. Further investigation determined that the analogs elicit a pyoverdin hyperproduction phenotype that is consistent with blockade of the BfrB-Bfd interaction and ensuing irreversible accumulation of iron in BfrB, with concomitant depletion of iron in the cytosol. The irreversible accumulation of iron in BfrB prompted by the 4-substituted isoindoline analogs was confirmed by visualization of BfrB-iron in P. aeruginosa cell lysates separated on native PAGE gels and stained for iron with Ferene S. Challenging P. aeruginosa cultures with a combination of commercial fluoroquinolone and our isoindoline analogs results in significantly lower cell survival relative to treatment with either antibiotic or analog alone. Collectively, these findings furnish proof of concept for the usefulness of small molecule probes designed to dysregulate bacterial iron homeostasis by targeting a protein-protein interaction pivotal for iron storage in the bacterial cell.
Small Molecule Inhibitors of the BfrB-Bfd Interaction Decrease Pseudomonas aeruginosa Fitness and Potentiate Fluoroquinolone Activity.,Punchi Hewage AND, Yao H, Nammalwar B, Gnanasekaran KK, Lovell S, Bunce RA, Eshelman K, Phaniraj SM, Lee MM, Peterson BR, Battaile KP, Reitz AB, Rivera M J Am Chem Soc. 2019 May 9. doi: 10.1021/jacs.9b00394. PMID:31038945[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Weeratunga SK, Gee CE, Lovell S, Zeng Y, Woodin CL, Rivera M. Binding of Pseudomonas aeruginosa apobacterioferritin-associated ferredoxin to bacterioferritin B promotes heme mediation of electron delivery and mobilization of core mineral iron. Biochemistry. 2009 Aug 11;48(31):7420-31. PMID:19575528 doi:10.1021/bi900561a
- ↑ Weeratunga SK, Lovell S, Yao H, Battaile KP, Fischer CJ, Gee CE, Rivera M. Structural Studies of Bacterioferritin B from Pseudomonas aeruginosa Suggest a Gating Mechanism for Iron Uptake via the Ferroxidase Center . Biochemistry. 2010 Jan 21. PMID:20067302 doi:10.1021/bi9015204
- ↑ Yao H, Wang Y, Lovell SW, Kumar R, Ruvinsky AM, Battaile KP, Vakser IA, Rivera M. The structure of the BfrB-Bfd complex reveals protein-protein interactions enabling iron release from bacterioferritin. J Am Chem Soc. 2012 Jul 19. PMID:22812654 doi:10.1021/ja305180n
- ↑ Yao H, Rui H, Kumar R, Eshelman K, Lovell S, Battaile KP, Im W, Rivera M. Concerted Motions Networking Pores and Distant Ferroxidase Centers Enable Bacterioferritin Function and Iron Traffic. Biochemistry. 2015 Jan 31. PMID:25640193 doi:http://dx.doi.org/10.1021/bi501255r
- ↑ Wang Y, Yao H, Cheng Y, Lovell SW, Battaile KP, Middaugh CR, Rivera M. Characterization of the Bacterioferritin/Bacterioferritin Associated Ferredoxin (BfrB:Bfd) Protein-Protein Interaction in Solution and Determination of Binding Energy Hot Spots. Biochemistry. 2015 Sep 28. PMID:26368531 doi:http://dx.doi.org/10.1021/acs.biochem.5b00937
- ↑ Eshelman K, Yao H, Punchi Hewage AND, Deay JJ, Chandler JR, Rivera M. Inhibiting the BfrB:Bfd interaction in Pseudomonas aeruginosa causes irreversible iron accumulation in bacterioferritin and iron deficiency in the bacterial cytosol. Metallomics. 2017 Jun 21;9(6):646-659. PMID:28318006 doi:10.1039/c7mt00042a
- ↑ Punchi Hewage AND, Yao H, Nammalwar B, Gnanasekaran KK, Lovell S, Bunce RA, Eshelman K, Phaniraj SM, Lee MM, Peterson BR, Battaile KP, Reitz AB, Rivera M. Small Molecule Inhibitors of the BfrB-Bfd Interaction Decrease Pseudomonas aeruginosa Fitness and Potentiate Fluoroquinolone Activity. J Am Chem Soc. 2019 May 9. doi: 10.1021/jacs.9b00394. PMID:31038945 doi:http://dx.doi.org/10.1021/jacs.9b00394
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