| Structural highlights
Function
BFD_PSEAE Required for mobilization of iron from the bacterioferritin (BFR) complex, composed of BfrB and FtnA in varying proportions; mobilization requires the [2Fe-2S] cluster of this protein (PubMed:19575528, PubMed:22812654, PubMed:26368531, PubMed:28318006, PubMed:30183257). 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 prior to its release as Fe(2+) (PubMed:19575528, PubMed:22812654).[1] [2] [3] [4] [5] [6]
Publication Abstract from PubMed
Mobilization of iron from bacterioferritin (BfrB) requires specific interactions with a [2Fe-2S] ferredoxin (Bfd). Blocking the BfrB:Bfd interaction results in irreversible iron accumulation in BfrB and iron deficiency in the cytosol [Eshelman, K., et al. (2017) Metallomics 9, 646-659]. The only known Bfd structure, which was obtained in complex with BfrB (Protein Data Bank entry 4E6K ), indicated a new fold and suggested that the stability of Bfd is aided by an anion binding site consisting of R26, R29, and K46. We investigated the Bfd fold using site-directed mutagenesis, X-ray crystallography, and biochemistry in solution. The X-ray structure, which is nearly identical to that of Bfd in the BfrB:Bfd complex, shows that the [2Fe-2S] cluster preorganizes residues at the BfrB:Bfd interface into a structure complementary to the Bfd binding site on BfrB. Studies in solution showed rapid loss of the [2Fe-2S] cluster at a low ionic strength but higher stability with an increasing ionic strength, thus supporting a structural anion binding site. Structures of the R26E and R26E/K46Y mutants are nearly identical to that of Bfd, except for a new network of hydrogen bonds stabilizing the region encompassing the former anion binding site. The stability of the R26E and R26E/K46Y mutants, which is weakly and completely independent of solution ionic strength, respectively, corroborates that Bfd requires an anion binding site. The mutations, which caused only small changes to the strength of the BfrB:Bfd interaction and mobilization of iron from BfrB, indicate that the anion binding site in Bfd serves primarily a structural role.
Bfd, a New Class of [2Fe-2S] Protein That Functions in Bacterial Iron Homeostasis, Requires a Structural Anion Binding Site.,Wijerathne H, Yao H, Wang Y, Lovell S, Battaile KP, Rivera M Biochemistry. 2018 Sep 13. doi: 10.1021/acs.biochem.8b00823. PMID:30183257[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
- ↑ 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
- ↑ 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:https://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
- ↑ Wijerathne H, Yao H, Wang Y, Lovell S, Battaile KP, Rivera M. Bfd, a New Class of [2Fe-2S] Protein That Functions in Bacterial Iron Homeostasis, Requires a Structural Anion Binding Site. Biochemistry. 2018 Sep 13. doi: 10.1021/acs.biochem.8b00823. PMID:30183257 doi:https://dx.doi.org/10.1021/acs.biochem.8b00823
- ↑ 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
- ↑ Wijerathne H, Yao H, Wang Y, Lovell S, Battaile KP, Rivera M. Bfd, a New Class of [2Fe-2S] Protein That Functions in Bacterial Iron Homeostasis, Requires a Structural Anion Binding Site. Biochemistry. 2018 Sep 13. doi: 10.1021/acs.biochem.8b00823. PMID:30183257 doi:https://dx.doi.org/10.1021/acs.biochem.8b00823
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