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Rydz L, Wróbel M, Jurkowska H. Sulfur Administration in Fe-S Cluster Homeostasis. Antioxidants (Basel) 2021; 10:antiox10111738. [PMID: 34829609 PMCID: PMC8614886 DOI: 10.3390/antiox10111738] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/25/2021] [Accepted: 10/27/2021] [Indexed: 11/24/2022] Open
Abstract
Mitochondria are the key organelles of Fe–S cluster synthesis. They contain the enzyme cysteine desulfurase, a scaffold protein, iron and electron donors, and specific chaperons all required for the formation of Fe–S clusters. The newly formed cluster can be utilized by mitochondrial Fe–S protein synthesis or undergo further transformation. Mitochondrial Fe–S cluster biogenesis components are required in the cytosolic iron–sulfur cluster assembly machinery for cytosolic and nuclear cluster supplies. Clusters that are the key components of Fe–S proteins are vulnerable and prone to degradation whenever exposed to oxidative stress. However, once degraded, the Fe–S cluster can be resynthesized or repaired. It has been proposed that sulfurtransferases, rhodanese, and 3-mercaptopyruvate sulfurtransferase, responsible for sulfur transfer from donor to nucleophilic acceptor, are involved in the Fe–S cluster formation, maturation, or reconstitution. In the present paper, we attempt to sum up our knowledge on the involvement of sulfurtransferases not only in sulfur administration but also in the Fe–S cluster formation in mammals and yeasts, and on reconstitution-damaged cluster or restoration of enzyme’s attenuated activity.
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2
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Li S, Liu Y, Li J, Zhao X, Yu D. Mechanisms of Ferroptosis and Application to Head and Neck Squamous Cell Carcinoma Treatments. DNA Cell Biol 2021; 40:720-732. [PMID: 33979530 DOI: 10.1089/dna.2021.0023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Many kinds of cancer cells are intrinsically sensitive to ferroptosis, and research interest regarding ferroptosis has been sparked by its significant role in many detrimental diseases. Ferroptosis is a novel type of iron-dependent cell death mediated by accumulation of reactive oxygen species and lipid peroxidation. Furthermore, a large number of small agents can induce ferroptosis in numerous kinds of cancer cells, including prostate cancer, pancreatic cancer, breast cancer, lymphomas, and renal cancer. These insights may help discover novel approaches for cancer therapeutic strategies; however, there is considerable uncertainty regarding ferroptosis in head and neck cancer (HNC). So far, no review of the current studies on this topic has been published. Therefore, we here elaborate the mechanisms of ferroptosis and summarize the latest findings regarding its role in HNC according to current literature. The respective findings shed light on the role of ferroptosis in HNC treatment with a number of important implications for future practice in HNC management, as outlined in this review.
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Affiliation(s)
- Shuang Li
- Department of Otolaryngology-Head and Neck Surgery, The Second Hospital of Jilin University, Changchun, People's Republic of China
| | - Yan Liu
- Department of Otolaryngology-Head and Neck Surgery, The Second Hospital of Jilin University, Changchun, People's Republic of China
| | - Jinqiu Li
- Department of Otolaryngology-Head and Neck Surgery, The Second Hospital of Jilin University, Changchun, People's Republic of China
| | - Xue Zhao
- Department of Otolaryngology-Head and Neck Surgery, The Second Hospital of Jilin University, Changchun, People's Republic of China
| | - Dan Yu
- Department of Otolaryngology-Head and Neck Surgery, The Second Hospital of Jilin University, Changchun, People's Republic of China
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3
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Gakh O, Ranatunga W, Galeano BK, Smith DS, Thompson JR, Isaya G. Defining the Architecture of the Core Machinery for the Assembly of Fe-S Clusters in Human Mitochondria. Methods Enzymol 2017; 595:107-160. [PMID: 28882199 DOI: 10.1016/bs.mie.2017.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Although Fe-S clusters may assemble spontaneously from elemental iron and sulfur in protein-free systems, the potential toxicity of free Fe2+, Fe3+, and S2- ions in aerobic environments underscores the requirement for specialized proteins to oversee the safe assembly of Fe-S clusters in living cells. Prokaryotes first developed multiprotein systems for Fe-S cluster assembly, from which mitochondria later derived their own system and became the main Fe-S cluster suppliers for eukaryotic cells. Early studies in yeast and human mitochondria indicated that Fe-S cluster assembly in eukaryotes is centered around highly conserved Fe-S proteins (human ISCU) that serve as scaffolds upon which new Fe-S clusters are assembled from (i) elemental sulfur, provided by a pyridoxal phosphate-dependent cysteine desulfurase (human NFS1) and its stabilizing-binding partner (human ISD11), and (ii) elemental iron, provided by an iron-binding protein of the frataxin family (human FXN). Further studies revealed that all of these proteins could form stable complexes that could reach molecular masses of megadaltons. However, the protein-protein interaction surfaces, catalytic mechanisms, and overall architecture of these macromolecular machines remained undefined for quite some time. The delay was due to difficulties inherent in reconstituting these very large multiprotein complexes in vitro or isolating them from cells in sufficient quantities to enable biochemical and structural studies. Here, we describe approaches we developed to reconstitute the human Fe-S cluster assembly machinery in Escherichia coli and to define its remarkable architecture.
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Affiliation(s)
| | | | - Belinda K Galeano
- Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States
| | | | | | - Grazia Isaya
- Mayo Clinic, Rochester, MN, United States; Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States; Mayo Clinic Children's Research Center, Rochester, MN, United States.
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4
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Galeano BK, Ranatunga W, Gakh O, Smith DY, Thompson JR, Isaya G. Zinc and the iron donor frataxin regulate oligomerization of the scaffold protein to form new Fe-S cluster assembly centers. Metallomics 2017; 9:773-801. [PMID: 28548666 PMCID: PMC5552075 DOI: 10.1039/c7mt00089h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/02/2017] [Indexed: 02/06/2023]
Abstract
Early studies of the bacterial Fe-S cluster assembly system provided structural details for how the scaffold protein and the cysteine desulfurase interact. This work and additional work on the yeast and human systems elucidated a conserved mechanism for sulfur donation but did not provide any conclusive insights into the mechanism for iron delivery from the iron donor, frataxin, to the scaffold. We previously showed that oligomerization is a mechanism by which yeast frataxin (Yfh1) can promote assembly of the core machinery for Fe-S cluster synthesis both in vitro and in cells, in such a manner that the scaffold protein, Isu1, can bind to Yfh1 independent of the presence of the cysteine desulfurase, Nfs1. Here, in the absence of Yfh1, Isu1 was found to exist in two forms, one mostly monomeric with limited tendency to dimerize, and one with a strong propensity to oligomerize. Whereas the monomeric form is stabilized by zinc, the loss of zinc promotes formation of dimer and higher order oligomers. However, upon binding to oligomeric Yfh1, both forms take on a similar symmetrical trimeric configuration that places the Fe-S cluster coordinating residues of Isu1 in close proximity of iron-binding residues of Yfh1. This configuration is suitable for docking of Nfs1 in a manner that provides a structural context for coordinate iron and sulfur donation to the scaffold. Moreover, distinct structural features suggest that in physiological conditions the zinc-regulated abundance of monomeric vs. oligomeric Isu1 yields [Yfh1]·[Isu1] complexes with different Isu1 configurations that afford unique functional properties for Fe-S cluster assembly and delivery.
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Affiliation(s)
- B. K. Galeano
- Department of Pediatric & Adolescent Medicine , Mayo Clinic , Rochester , Minnesota , USA . ;
- Department of Biochemistry & Molecular Biology , Mayo Clinic , Rochester , Minnesota , USA
- Mayo Clinic Graduate School of Biomedical Sciences , Rochester , Minnesota , USA
| | - W. Ranatunga
- Department of Pediatric & Adolescent Medicine , Mayo Clinic , Rochester , Minnesota , USA . ;
- Mayo Clinic Children's Research Center , Rochester , Minnesota , USA
| | - O. Gakh
- Department of Pediatric & Adolescent Medicine , Mayo Clinic , Rochester , Minnesota , USA . ;
- Mayo Clinic Children's Research Center , Rochester , Minnesota , USA
| | - D. Y. Smith
- Department of Pediatric & Adolescent Medicine , Mayo Clinic , Rochester , Minnesota , USA . ;
- Mayo Clinic Children's Research Center , Rochester , Minnesota , USA
| | - J. R. Thompson
- Department of Biochemistry & Molecular Biology , Mayo Clinic , Rochester , Minnesota , USA
| | - G. Isaya
- Department of Pediatric & Adolescent Medicine , Mayo Clinic , Rochester , Minnesota , USA . ;
- Department of Biochemistry & Molecular Biology , Mayo Clinic , Rochester , Minnesota , USA
- Mayo Clinic Children's Research Center , Rochester , Minnesota , USA
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5
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Friemel M, Marelja Z, Li K, Leimkühler S. The N-Terminus of Iron-Sulfur Cluster Assembly Factor ISD11 Is Crucial for Subcellular Targeting and Interaction with l-Cysteine Desulfurase NFS1. Biochemistry 2017; 56:1797-1808. [PMID: 28271877 DOI: 10.1021/acs.biochem.6b01239] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Assembly of iron-sulfur (FeS) clusters is an important process in living cells. The initial sulfur mobilization step for FeS cluster biosynthesis is catalyzed by l-cysteine desulfurase NFS1, a reaction that is localized in mitochondria in humans. In humans, the function of NFS1 depends on the ISD11 protein, which is required to stabilize its structure. The NFS1/ISD11 complex further interacts with scaffold protein ISCU and regulator protein frataxin, thereby forming a quaternary complex for FeS cluster formation. It has been suggested that the role of ISD11 is not restricted to its role in stabilizing the structure of NFS1, because studies of single-amino acid variants of ISD11 additionally demonstrated its importance for the correct assembly of the quaternary complex. In this study, we are focusing on the N-terminal region of ISD11 to determine the role of N-terminal amino acids in the formation of the complex with NFS1 and to reveal the mitochondrial targeting sequence for subcellular localization. Our in vitro studies with the purified proteins and in vivo studies in a cellular system show that the first 10 N-terminal amino acids of ISD11 are indispensable for the activity of NFS1 and especially the conserved "LYR" motif is essential for the role of ISD11 in forming a stable and active complex with NFS1.
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Affiliation(s)
- Martin Friemel
- Institut für Biochemie und Biologie, Molekulare Enzymologie, Universität Potsdam , Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
| | - Zvonimir Marelja
- Imagine Institute, Université Paris Descartes, Sorbonne Paris Cité , 75015 Paris, France
| | - Kuanyu Li
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University , Nanjing, China
| | - Silke Leimkühler
- Institut für Biochemie und Biologie, Molekulare Enzymologie, Universität Potsdam , Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
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6
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Tamarit J, Obis È, Ros J. Oxidative stress and altered lipid metabolism in Friedreich ataxia. Free Radic Biol Med 2016; 100:138-146. [PMID: 27296838 DOI: 10.1016/j.freeradbiomed.2016.06.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 06/07/2016] [Accepted: 06/10/2016] [Indexed: 12/31/2022]
Abstract
Friedreich ataxia is a genetic disease caused by the deficiency of frataxin, a mitochondrial protein. Frataxin deficiency impacts in the cell physiology at several levels. One of them is oxidative stress with consequences in terms of protein dysfunctions and metabolic alterations. Among others, alterations in lipid metabolism have been observed in several models of the disease. In this review we summarize the current knowledge of the molecular basis of the disease, the relevance of oxidative stress and the therapeutic strategies based on reduction of mitochondrial reactive oxygen species production. Finally, we will focus the interest in alterations of lipid metabolism as a consequence of mitochondrial dysfunction and describe the therapeutic approaches based on targeting lipid metabolism.
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Affiliation(s)
- Jordi Tamarit
- Departament de Ciències Mèdiques Bàsiques, IRB-Lleida, Universitat de Lleida, Lleida, Spain
| | - Èlia Obis
- Departament de Ciències Mèdiques Bàsiques, IRB-Lleida, Universitat de Lleida, Lleida, Spain
| | - Joaquim Ros
- Departament de Ciències Mèdiques Bàsiques, IRB-Lleida, Universitat de Lleida, Lleida, Spain.
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Gakh O, Ranatunga W, Smith DY, Ahlgren EC, Al-Karadaghi S, Thompson JR, Isaya G. Architecture of the Human Mitochondrial Iron-Sulfur Cluster Assembly Machinery. J Biol Chem 2016; 291:21296-21321. [PMID: 27519411 PMCID: PMC5076535 DOI: 10.1074/jbc.m116.738542] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 08/10/2016] [Indexed: 11/06/2022] Open
Abstract
Fe-S clusters, essential cofactors needed for the activity of many different enzymes, are assembled by conserved protein machineries inside bacteria and mitochondria. As the architecture of the human machinery remains undefined, we co-expressed in Escherichia coli the following four proteins involved in the initial step of Fe-S cluster synthesis: FXN42-210 (iron donor); [NFS1]·[ISD11] (sulfur donor); and ISCU (scaffold upon which new clusters are assembled). We purified a stable, active complex consisting of all four proteins with 1:1:1:1 stoichiometry. Using negative staining transmission EM and single particle analysis, we obtained a three-dimensional model of the complex with ∼14 Å resolution. Molecular dynamics flexible fitting of protein structures docked into the EM map of the model revealed a [FXN42-210]24·[NFS1]24·[ISD11]24·[ISCU]24 complex, consistent with the measured 1:1:1:1 stoichiometry of its four components. The complex structure fulfills distance constraints obtained from chemical cross-linking of the complex at multiple recurring interfaces, involving hydrogen bonds, salt bridges, or hydrophobic interactions between conserved residues. The complex consists of a central roughly cubic [FXN42-210]24·[ISCU]24 sub-complex with one symmetric ISCU trimer bound on top of one symmetric FXN42-210 trimer at each of its eight vertices. Binding of 12 [NFS1]2·[ISD11]2 sub-complexes to the surface results in a globular macromolecule with a diameter of ∼15 nm and creates 24 Fe-S cluster assembly centers. The organization of each center recapitulates a previously proposed conserved mechanism for sulfur donation from NFS1 to ISCU and reveals, for the first time, a path for iron donation from FXN42-210 to ISCU.
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Affiliation(s)
- Oleksandr Gakh
- From the Departments of Pediatric and Adolescent Medicine and Biochemistry Molecular Biology, Mayo Clinic Children's Research Center, and
| | - Wasantha Ranatunga
- From the Departments of Pediatric and Adolescent Medicine and Biochemistry Molecular Biology, Mayo Clinic Children's Research Center, and
| | - Douglas Y Smith
- From the Departments of Pediatric and Adolescent Medicine and Biochemistry Molecular Biology, Mayo Clinic Children's Research Center, and
| | - Eva-Christina Ahlgren
- the Center for Molecular Protein Science, Institute for Chemistry and Chemical Engineering, Lund University, P. O. Box 124, SE-221 00 Lund, Sweden
| | - Salam Al-Karadaghi
- the Center for Molecular Protein Science, Institute for Chemistry and Chemical Engineering, Lund University, P. O. Box 124, SE-221 00 Lund, Sweden
| | - James R Thompson
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota 55905 and
| | - Grazia Isaya
- From the Departments of Pediatric and Adolescent Medicine and Biochemistry Molecular Biology, Mayo Clinic Children's Research Center, and
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8
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Yan R, Friemel M, Aloisi C, Huynen M, Taylor IA, Leimkühler S, Pastore A. The Eukaryotic-Specific ISD11 Is a Complex-Orphan Protein with Ability to Bind the Prokaryotic IscS. PLoS One 2016; 11:e0157895. [PMID: 27427956 PMCID: PMC4948766 DOI: 10.1371/journal.pone.0157895] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 06/07/2016] [Indexed: 11/18/2022] Open
Abstract
The eukaryotic protein Isd11 is a chaperone that binds and stabilizes the central component of the essential metabolic pathway responsible for formation of iron-sulfur clusters in mitochondria, the desulfurase Nfs1. Little is known about the exact role of Isd11. Here, we show that human Isd11 (ISD11) is a helical protein which exists in solution as an equilibrium between monomer, dimeric and tetrameric species when in the absence of human Nfs1 (NFS1). We also show that, surprisingly, recombinant ISD11 expressed in E. coli co-purifies with the bacterial orthologue of NFS1, IscS. Binding is weak but specific suggesting that, despite the absence of Isd11 sequences in bacteria, there is enough conservation between the two desulfurases to retain a similar mode of interaction. This knowledge may inform us on the conservation of the mode of binding of Isd11 to the desulfurase. We used evolutionary evidence to suggest Isd11 residues involved in the interaction.
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Affiliation(s)
- Robert Yan
- Maurice Wohl Institute, King’s College London, 5 Cutcombe Rd, SE5, London, United Kingdom
| | - Martin Friemel
- Department of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Claudia Aloisi
- Maurice Wohl Institute, King’s College London, 5 Cutcombe Rd, SE5, London, United Kingdom
| | - Martijn Huynen
- CMBI 260, Radboud University Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Ian A. Taylor
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London, NW7 1AA, United Kingdom
| | - Silke Leimkühler
- Department of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Annalisa Pastore
- Maurice Wohl Institute, King’s College London, 5 Cutcombe Rd, SE5, London, United Kingdom
- * E-mail:
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9
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Ranatunga W, Gakh O, Galeano BK, Smith DY, Söderberg CAG, Al-Karadaghi S, Thompson JR, Isaya G. Architecture of the Yeast Mitochondrial Iron-Sulfur Cluster Assembly Machinery: THE SUB-COMPLEX FORMED BY THE IRON DONOR, Yfh1 PROTEIN, AND THE SCAFFOLD, Isu1 PROTEIN. J Biol Chem 2016; 291:10378-98. [PMID: 26941001 PMCID: PMC4858984 DOI: 10.1074/jbc.m115.712414] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 02/26/2016] [Indexed: 12/18/2022] Open
Abstract
The biosynthesis of Fe-S clusters is a vital process involving the delivery of elemental iron and sulfur to scaffold proteins via molecular interactions that are still poorly defined. We reconstituted a stable, functional complex consisting of the iron donor, Yfh1 (yeast frataxin homologue 1), and the Fe-S cluster scaffold, Isu1, with 1:1 stoichiometry, [Yfh1]24·[Isu1]24 Using negative staining transmission EM and single particle analysis, we obtained a three-dimensional reconstruction of this complex at a resolution of ∼17 Å. In addition, via chemical cross-linking, limited proteolysis, and mass spectrometry, we identified protein-protein interaction surfaces within the complex. The data together reveal that [Yfh1]24·[Isu1]24 is a roughly cubic macromolecule consisting of one symmetric Isu1 trimer binding on top of one symmetric Yfh1 trimer at each of its eight vertices. Furthermore, molecular modeling suggests that two subunits of the cysteine desulfurase, Nfs1, may bind symmetrically on top of two adjacent Isu1 trimers in a manner that creates two putative [2Fe-2S] cluster assembly centers. In each center, conserved amino acids known to be involved in sulfur and iron donation by Nfs1 and Yfh1, respectively, are in close proximity to the Fe-S cluster-coordinating residues of Isu1. We suggest that this architecture is suitable to ensure concerted and protected transfer of potentially toxic iron and sulfur atoms to Isu1 during Fe-S cluster assembly.
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Affiliation(s)
- Wasantha Ranatunga
- From the Departments of Pediatric and Adolescent Medicine and Biochemistry and Molecular Biology, and the Mayo Clinic Children's Research Center, and
| | - Oleksandr Gakh
- From the Departments of Pediatric and Adolescent Medicine and Biochemistry and Molecular Biology, and the Mayo Clinic Children's Research Center, and
| | - Belinda K Galeano
- From the Departments of Pediatric and Adolescent Medicine and Biochemistry and Molecular Biology, and the Mayo Clinic Children's Research Center, and
| | - Douglas Y Smith
- From the Departments of Pediatric and Adolescent Medicine and Biochemistry and Molecular Biology, and the Mayo Clinic Children's Research Center, and
| | - Christopher A G Söderberg
- the Center for Molecular Protein Science, Institute for Chemistry and Chemical Engineering, Lund University, P. O. Box 124, SE-221 00 Lund, Sweden
| | - Salam Al-Karadaghi
- the Center for Molecular Protein Science, Institute for Chemistry and Chemical Engineering, Lund University, P. O. Box 124, SE-221 00 Lund, Sweden
| | - James R Thompson
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota 55905 and
| | - Grazia Isaya
- From the Departments of Pediatric and Adolescent Medicine and Biochemistry and Molecular Biology, and the Mayo Clinic Children's Research Center, and
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10
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Mielcarek A, Blauenburg B, Miethke M, Marahiel MA. Molecular insights into frataxin-mediated iron supply for heme biosynthesis in Bacillus subtilis. PLoS One 2015; 10:e0122538. [PMID: 25826316 PMCID: PMC4380498 DOI: 10.1371/journal.pone.0122538] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 02/13/2015] [Indexed: 11/19/2022] Open
Abstract
Iron is required as an element to sustain life in all eukaryotes and most bacteria. Although several bacterial iron acquisition strategies have been well explored, little is known about the intracellular trafficking pathways of iron and its entry into the systems for co-factor biogenesis. In this study, we investigated the iron-dependent process of heme maturation in Bacillus subtilis and present, for the first time, structural evidence for the physical interaction of a frataxin homologue (Fra), which is suggested to act as a regulatory component as well as an iron chaperone in different cellular pathways, and a ferrochelatase (HemH), which catalyses the final step of heme b biogenesis. Specific interaction between Fra and HemH was observed upon co-purification from crude cell lysates and, further, by using the recombinant proteins for analytical size-exclusion chromatography. Hydrogen-deuterium exchange experiments identified the landscape of the Fra/HemH interaction interface and revealed Fra as a specific ferrous iron donor for the ferrochelatase HemH. The functional utilisation of the in vitro-generated heme b co-factor upon Fra-mediated iron transfer was confirmed by using the B. subtilis nitric oxide synthase bsNos as a metabolic target enzyme. Complementary mutational analyses confirmed that Fra acts as an essential component for maturation and subsequent targeting of the heme b co-factor, hence representing a key player in the iron-dependent physiology of B. subtilis.
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Affiliation(s)
- Andreas Mielcarek
- Philipps-University Marburg, Department of Chemistry/Biochemistry, Marburg, Germany
| | - Bastian Blauenburg
- Philipps-University Marburg, Department of Chemistry/Biochemistry, Marburg, Germany
| | - Marcus Miethke
- Philipps-University Marburg, Department of Chemistry/Biochemistry, Marburg, Germany
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, United States of America
| | - Mohamed A. Marahiel
- Philipps-University Marburg, Department of Chemistry/Biochemistry, Marburg, Germany
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Majewska J, Ciesielski SJ, Schilke B, Kominek J, Blenska A, Delewski W, Song JY, Marszalek J, Craig EA, Dutkiewicz R. Binding of the chaperone Jac1 protein and cysteine desulfurase Nfs1 to the iron-sulfur cluster scaffold Isu protein is mutually exclusive. J Biol Chem 2013; 288:29134-42. [PMID: 23946486 DOI: 10.1074/jbc.m113.503524] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Biogenesis of mitochondrial iron-sulfur (Fe/S) cluster proteins requires the interaction of multiple proteins with the highly conserved 14-kDa scaffold protein Isu, on which clusters are built prior to their transfer to recipient proteins. For example, the assembly process requires the cysteine desulfurase Nfs1, which serves as the sulfur donor for cluster assembly. The transfer process requires Jac1, a J-protein Hsp70 cochaperone. We recently identified three residues on the surface of Jac1 that form a hydrophobic patch critical for interaction with Isu. The results of molecular modeling of the Isu1-Jac1 interaction, which was guided by these experimental data and structural/biophysical information available for bacterial homologs, predicted the importance of three hydrophobic residues forming a patch on the surface of Isu1 for interaction with Jac1. Using Isu variants having alterations in residues that form the hydrophobic patch on the surface of Isu, this prediction was experimentally validated by in vitro binding assays. In addition, Nfs1 was found to require the same hydrophobic residues of Isu for binding, as does Jac1, suggesting that Jac1 and Nfs1 binding is mutually exclusive. In support of this conclusion, Jac1 and Nfs1 compete for binding to Isu. Evolutionary analysis revealed that residues involved in these interactions are conserved and that they are critical residues for the biogenesis of Fe/S cluster protein in vivo. We propose that competition between Jac1 and Nfs1 for Isu binding plays an important role in transitioning the Fe/S cluster biogenesis machinery from the cluster assembly step to the Hsp70-mediated transfer of the Fe/S cluster to recipient proteins.
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Affiliation(s)
- Julia Majewska
- From the University of Gdansk, Intercollegiate Faculty of Biotechnology, Gdansk 80822, Poland and
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