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Bennett SP, Crack JC, Puglisi R, Pastore A, Le Brun NE. Native mass spectrometric studies of IscSU reveal a concerted, sulfur-initiated mechanism of iron-sulfur cluster assembly. Chem Sci 2022; 14:78-95. [PMID: 36605734 PMCID: PMC9769115 DOI: 10.1039/d2sc04169c] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 11/13/2022] [Indexed: 11/16/2022] Open
Abstract
Iron-sulfur (Fe-S) clusters are cofactors essential for life. Though the proteins that function in the assembly of Fe-S clusters are well known, details of the molecular mechanism are less well established. The Isc (iron-sulfur cluster) biogenesis apparatus is widespread in bacteria and is the closest homologue to the human system. Mutations in certain components of the human system lead to disease, and so further studies of this system could be important for developing strategies for medical treatments. We have studied two core components of the Isc biogenesis system: IscS, a cysteine desulfurase; and IscU, a scaffold protein on which clusters are built before subsequent transfer onto recipient apo-proteins. Fe2+-binding, sulfur transfer, and formation of a [2Fe-2S] was followed by a range of techniques, including time-resolved mass spectrometry, and intermediate and product species were unambiguously identified through isotopic substitution experiments using 57Fe and 34S. Under cluster synthesis conditions, sulfur adducts and the [2Fe-2S] cluster product readily accumulated on IscU, but iron adducts (other than the cluster itself) were not observed at physiologically relevant Fe2+ concentrations. Our data indicate that either Fe2+ or sulfur transfer can occur first, but that the transfer of sulfane sulfur (S0) to IscU must occur first if Zn2+ is bound to IscU, suggesting that it is the key step that initiates cluster assembly. Following this, [2Fe-2S] cluster formation is a largely concerted reaction once Fe2+ is introduced.
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Affiliation(s)
- Sophie P. Bennett
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Jason C. Crack
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Rita Puglisi
- The Wohl Institute, King's College London, Denmark Hill CampusLondon SE5 8AFUK
| | - Annalisa Pastore
- The Wohl Institute, King's College London, Denmark Hill CampusLondon SE5 8AFUK
| | - Nick E. Le Brun
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East AngliaNorwich Research ParkNorwichNR4 7TJUK
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2
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Lin CW, Oney-Hawthorne SD, Kuo ST, Barondeau DP, Russell DH. Mechanistic Insights into IscU Conformation Regulation for Fe-S Cluster Biogenesis Revealed by Variable Temperature Electrospray Ionization Native Ion Mobility Mass Spectrometry. Biochemistry 2022; 61:2733-2741. [PMID: 36351081 PMCID: PMC10009881 DOI: 10.1021/acs.biochem.2c00429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Iron-sulfur (Fe-S) cluster (ISC) cofactors are required for the function of many critical cellular processes. In the ISC Fe-S cluster biosynthetic pathway, IscU assembles Fe-S cluster intermediates from iron, electrons, and inorganic sulfur, which is provided by the cysteine desulfurase enzyme IscS. IscU also binds to Zn, which mimics and competes for binding with the Fe-S cluster. Crystallographic and nuclear magnetic resonance spectroscopic studies reveal that IscU is a metamorphic protein that exists in multiple conformational states, which include at least a structured form and a disordered form. The structured form of IscU is favored by metal binding and is stable in a narrow temperature range, undergoing both cold and hot denaturation. Interestingly, the form of IscU that binds IscS and functions in Fe-S cluster assembly remains controversial. Here, results from variable temperature electrospray ionization (vT-ESI) native ion mobility mass spectrometry (nIM-MS) establish that IscU exists in structured, intermediate, and disordered forms that rearrange to more extended conformations at higher temperatures. A comparison of Zn-IscU and apo-IscU reveals that Zn(II) binding attenuates the cold/heat denaturation of IscU, promotes refolding of IscU, favors the structured and intermediate conformations, and inhibits the disordered high charge states. Overall, these findings provide a structural rationalization for the role of Zn(II) in stabilizing IscU conformations and IscS in altering the IscU active site to prepare for Zn(II) release and cluster synthesis. This work highlights how vT-ESI-nIM-MS can be applied as a powerful tool in mechanistic enzymology by providing details of relationships among temperature, protein conformations, and ligand/protein binding.
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Affiliation(s)
- Cheng-Wei Lin
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, United States
| | - Shelby D Oney-Hawthorne
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, United States
| | - Syuan-Ting Kuo
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, United States
| | - David P Barondeau
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, United States
| | - David H Russell
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, United States
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3
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Marszalek J, Craig EA. Interaction of client—the scaffold on which FeS clusters are build—with J-domain protein Hsc20 and its evolving Hsp70 partners. Front Mol Biosci 2022; 9:1034453. [PMID: 36310602 PMCID: PMC9596805 DOI: 10.3389/fmolb.2022.1034453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 09/26/2022] [Indexed: 12/04/2022] Open
Abstract
In cells molecular chaperone systems consisting of Hsp70 and its obligatory J-domain protein (JDP) co-chaperones transiently interact with a myriad of client proteins—with JDPs typically recruiting their partner Hsp70 to interact with particular clients. The fundamentals of this cyclical interactions between JDP/Hsp70 systems and clients are well established. Much less is known about other aspects of JDP/Hsp70 system function, including how such systems evolved over time. Here we discuss the JDP/Hsp70 system involved in the biogenesis of iron-sulfur (FeS) clusters. Interaction between the client protein, the scaffold on which clusters are built, and its specialized JDP Hsc20 has stayed constant. However, the system’s Hsp70 has changed at least twice. In some species Hsc20’s Hsp70 partner interacts only with the scaffold, in others it has many JDP partners in addition to Hsc20 and interacts with many client proteins. Analysis of this switching of Hsp70 partners has provided insight into the insulation of JDP/Hsp70 systems from one another that can occur when more than one Hsp70 is present in a cellular compartment, as well as how competition among JDPs is balanced when an Hsp70 partner is shared amongst a number of JDPs. Of particularly broad relevance, even though the scaffold’s interactions with Hsc20 and Hsp70 are functionally critical for the biogenesis of FeS cluster-containing proteins, it is the modulation of the Hsc20-Hsp70 interaction per se that allows Hsc20 to function with such different Hsp70 partners.
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Affiliation(s)
- Jaroslaw Marszalek
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
- *Correspondence: Jaroslaw Marszalek, ; Elizabeth A. Craig,
| | - Elizabeth A. Craig
- Department of Biochemistry, University of Wisconsin—Madison, Madison, WI, United States
- *Correspondence: Jaroslaw Marszalek, ; Elizabeth A. Craig,
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4
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Site-Differentiated Iron–Sulfur Cluster Ligation Affects Flavin-Based Electron Bifurcation Activity. Metabolites 2022; 12:metabo12090823. [PMID: 36144227 PMCID: PMC9503767 DOI: 10.3390/metabo12090823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 08/25/2022] [Accepted: 08/28/2022] [Indexed: 11/16/2022] Open
Abstract
Electron bifurcation is an elegant mechanism of biological energy conversion that effectively couples three different physiologically relevant substrates. As such, enzymes that perform this function often play critical roles in modulating cellular redox metabolism. One such enzyme is NADH-dependent reduced-ferredoxin: NADP+ oxidoreductase (NfnSL), which couples the thermodynamically favorable reduction of NAD+ to drive the unfavorable reduction of ferredoxin from NADPH. The interaction of NfnSL with its substrates is constrained to strict stoichiometric conditions, which ensures minimal energy losses from non-productive intramolecular electron transfer reactions. However, the determinants for this are not well understood. One curious feature of NfnSL is that both initial acceptors of bifurcated electrons are unique iron–sulfur (FeS) clusters containing one non-cysteinyl ligand each. The biochemical impact and mechanistic roles of site-differentiated FeS ligands are enigmatic, despite their incidence in many redox active enzymes. Herein, we describe the biochemical study of wild-type NfnSL and a variant in which one of the site-differentiated ligands has been replaced with a cysteine. Results of dye-based steady-state kinetics experiments, substrate-binding measurements, biochemical activity assays, and assessments of electron distribution across the enzyme indicate that this site-differentiated ligand in NfnSL plays a role in maintaining fidelity of the coordinated reactions performed by the two electron transfer pathways. Given the commonality of these cofactors, our findings have broad implications beyond electron bifurcation and mechanistic biochemistry and may inform on means of modulating the redox balance of the cell for targeted metabolic engineering approaches.
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5
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Lubner CE, Artz JH, Mulder DW, Oza A, Ward RJ, Williams SG, Jones AK, Peters JW, Smalyukh II, Bharadwaj VS, King PW. A site-differentiated [4Fe-4S] cluster controls electron transfer reactivity of Clostridium acetobutylicum [FeFe]-hydrogenase I. Chem Sci 2022; 13:4581-4588. [PMID: 35656134 PMCID: PMC9019909 DOI: 10.1039/d1sc07120c] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 03/24/2022] [Indexed: 01/11/2023] Open
Abstract
One of the many functions of reduction–oxidation (redox) cofactors is to mediate electron transfer in biological enzymes catalyzing redox-based chemical transformation reactions. There are numerous examples of enzymes that utilize redox cofactors to form electron transfer relays to connect catalytic sites to external electron donors and acceptors. The compositions of relays are diverse and tune transfer thermodynamics and kinetics towards the chemical reactivity of the enzyme. Diversity in relay design is exemplified among different members of hydrogenases, enzymes which catalyze reversible H2 activation, which also couple to diverse types of donor and acceptor molecules. The [FeFe]-hydrogenase I from Clostridium acetobutylicum (CaI) is a member of a large family of structurally related enzymes where interfacial electron transfer is mediated by a terminal, non-canonical, His-coordinated, [4Fe–4S] cluster. The function of His coordination was examined by comparing the biophysical properties and reactivity to a Cys substituted variant of CaI. This demonstrated that His coordination strongly affected the distal [4Fe–4S] cluster spin state, spin pairing, and spatial orientations of molecular orbitals, with a minor effect on reduction potential. The deviations in these properties by substituting His for Cys in CaI, correlated with pronounced changes in electron transfer and reactivity with the native electron donor–acceptor ferredoxin. The results demonstrate that differential coordination of the surface localized [4Fe–4S]His cluster in CaI is utilized to control intermolecular and intramolecular electron transfer where His coordination creates a physical and electronic environment that enables facile electron exchange between electron carrier molecules and the iron–sulfur cluster relay for coupling to reversible H2 activation at the catalytic site. Histidine coordination of the distal [4Fe–4S] cluster in [FeFe]-hydrogenase was demonstrated to tune the cluster spin-states, spin-pairing and surrounding molecular orbitals to enable more facile electron transfer compared to cysteine coordination.![]()
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Affiliation(s)
| | - Jacob H Artz
- National Renewable Energy Laboratory Golden Colorado USA
| | - David W Mulder
- National Renewable Energy Laboratory Golden Colorado USA
| | - Aisha Oza
- National Renewable Energy Laboratory Golden Colorado USA
| | - Rachel J Ward
- Department of Physics, University of Colorado Boulder Boulder Colorado USA
| | - S Garrett Williams
- School of Molecular Sciences, Arizona State University Tempe Arizona USA.,Sandia National Laboratories Albuquerque New Mexico USA
| | - Anne K Jones
- School of Molecular Sciences, Arizona State University Tempe Arizona USA
| | - John W Peters
- Institute of Biological Chemistry, Washington State University Pullman Washington USA
| | - Ivan I Smalyukh
- Department of Physics, University of Colorado Boulder Boulder Colorado USA.,Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado Boulder Boulder Colorado USA
| | | | - Paul W King
- National Renewable Energy Laboratory Golden Colorado USA .,Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado Boulder Boulder Colorado USA
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6
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Hinton TV, Batelu S, Gleason N, Stemmler TL. Molecular characteristics of proteins within the mitochondrial Fe-S cluster assembly complex. Micron 2021; 153:103181. [PMID: 34823116 DOI: 10.1016/j.micron.2021.103181] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 11/29/2022]
Abstract
Iron-Sulfur (Fe-S) clusters are essential for life, as they are widely utilized in nearly every biochemical pathway. When bound to proteins, Fe-S clusters assist in catalysis, signal recognition, and energy transfer events, as well as additional cellular pathways including cellular respiration and DNA repair and replication. In Eukaryotes, Fe-S clusters are produced through coordinated activity by mitochondrial Iron-Sulfur Cluster (ISC) assembly pathway proteins through direct assembly, or through the production of the activated sulfur substrate used by the Cytosolic Iron-Sulfur Cluster Assembly (CIA) pathway. In the mitochondria, Fe-S cluster assembly is accomplished through the coordinated activity of the ISC pathway protein complex composed of a cysteine desulfurase, a scaffold protein, the accessory ISD11 protein, the acyl carrier protein, frataxin, and a ferredoxin; downstream events that accomplish Fe-S cluster transfer and delivery are driven by additional chaperone/delivery proteins that interact with the ISC assembly complex. Deficiency in human production or activity of Fe-S cluster containing proteins is often detrimental to cell and organism viability. Here we summarize what is known about the structure and functional activities of the proteins involved in the early steps of assembling [2Fe-2S] clusters before they are transferred to proteins devoted to their delivery. Our goal is to provide a comprehensive overview of how the ISC assembly apparatus proteins interact to make the Fe-S cluster which can be delivered to proteins downstream to the assembly event.
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Affiliation(s)
- Tiara V Hinton
- Department of Pharmaceutical Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI 48201, USA.
| | - Sharon Batelu
- Department of Pharmaceutical Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI 48201, USA.
| | - Noah Gleason
- Department of Pharmaceutical Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI 48201, USA.
| | - Timothy L Stemmler
- Department of Pharmaceutical Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI 48201, USA.
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7
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Mohammad Sadik, Mohammad Afsar, Ramachandran R, Habib S. [Fe-S] biogenesis and unusual assembly of the ISC scaffold complex in the Plasmodium falciparum mitochondrion. Mol Microbiol 2021; 116:606-623. [PMID: 34032321 DOI: 10.1111/mmi.14735] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 05/06/2021] [Accepted: 05/06/2021] [Indexed: 12/16/2022]
Abstract
The malaria parasite harbors two [Fe-S] biogenesis pathways of prokaryotic origin-the SUF and ISC systems in the apicoplast and mitochondrion, respectively. While the SUF machinery has been delineated, there is little experimental evidence on the ISC pathway. We confirmed mitochondrial targeting of Plasmodium falciparum ISC proteins followed by analyses of cysteine desulfurase, scaffold, and [Fe-S]-carrier components. PfIscU functioned as the scaffold in complex with the PfIscS-PfIsd11 cysteine desulfurase and could directly assemble [4Fe-4S] without prior [2Fe-2S] formation seen in other homologs. Small angle X-ray scattering and spectral studies showed that PfIscU, a trimer, bound one [4Fe-4S]. In a deviation from reported complexes from other organisms, the P. falciparum desulfurase-scaffold complex assembled around a PfIscS tetramer instead of a dimer, resulting in a symmetric hetero-hexamer [2× (2PfIscS-2PfIsd11-2PfIscU)]. PfIscU directly transferred [4Fe-4S] to the apo-protein aconitase B thus abrogating the requirement of intermediary proteins for conversion of [2Fe-2S] to [4Fe-4S] before transfer to [4Fe-4S]-recipients. Among the putative cluster-carriers, PfIscA2 was more efficient than PfNifU-like protein; PfIscA1 primarily bound iron, suggesting its potential role as a Fe2+ carrier/donor. Our results identify the core P. falciparum ISC machinery and reveal unique features compared with those in bacteria or yeast and human mitochondria.
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Affiliation(s)
- Mohammad Sadik
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India
| | - Mohammad Afsar
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India
| | - Ravishankar Ramachandran
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India
| | - Saman Habib
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India
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8
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Kunichika K, Nakamura R, Fujishiro T, Takahashi Y. The Structure of the Dimeric State of IscU Harboring Two Adjacent [2Fe-2S] Clusters Provides Mechanistic Insights into Cluster Conversion to [4Fe-4S]. Biochemistry 2021; 60:1569-1572. [PMID: 33938220 DOI: 10.1021/acs.biochem.1c00112] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
IscU serves as a scaffold for the de novo assembly of a [2Fe-2S] cluster prior to its delivery to recipient protein. It has also been proposed that on one dimer of bacterial IscU, two [2Fe-2S] clusters can be converted into a single [4Fe-4S] cluster. However, lack of structural information about the dimeric state of IscU has hindered our understanding of the underlying mechanisms. In this study, we determine the X-ray crystal structure of IscU from the thermophilic archaeon Methanothrix thermoacetophila and demonstrate a dimer structure of IscU in which two [2Fe-2S] clusters are facing each other in close proximity at the dimer interface. Our structure also reveals for the first time that Asp40 serves as a fourth ligand to the [2Fe-2S] cluster with three Cys ligands in each monomer, consistent with previous spectroscopic data. We confirm by EPR spectroscopic analysis that in solution two adjacent [2Fe-2S] clusters in the wild-type dimer are converted to a [4Fe-4S] cluster via reductive coupling. Furthermore, we find that the H106A substitution abolishes the reductive conversion to the [4Fe-4S] cluster without structural alteration, suggesting that His106 is functionally involved in this process. Overall, these findings provide a structural explanation for the assembly and conversion of Fe-S clusters on IscU and highlight a dynamic process that advances via association and dissociation of the IscU dimer.
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Affiliation(s)
- Kouhei Kunichika
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Ryosuke Nakamura
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Takashi Fujishiro
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Yasuhiro Takahashi
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
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9
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Olmos J, Pignataro MF, Benítez dos Santos AB, Bringas M, Klinke S, Kamenetzky L, Velazquez F, Santos J. A Highly Conserved Iron-Sulfur Cluster Assembly Machinery between Humans and Amoeba Dictyostelium discoideum: The Characterization of Frataxin. Int J Mol Sci 2020; 21:E6821. [PMID: 32957566 PMCID: PMC7554988 DOI: 10.3390/ijms21186821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/05/2020] [Accepted: 09/14/2020] [Indexed: 12/17/2022] Open
Abstract
Several biological activities depend on iron-sulfur clusters ([Fe-S]). Even though they are well-known in several organisms their function and metabolic pathway were poorly understood in the majority of the organisms. We propose to use the amoeba Dictyostelium discoideum, as a biological model to study the biosynthesis of [Fe-S] at the molecular, cellular and organism levels. First, we have explored the D. discoideum genome looking for genes corresponding to the subunits that constitute the molecular machinery for Fe-S cluster assembly and, based on the structure of the mammalian supercomplex and amino acid conservation profiles, we inferred the full functionality of the amoeba machinery. After that, we expressed the recombinant mature form of D. discoideum frataxin protein (DdFXN), the kinetic activator of this pathway. We characterized the protein and its conformational stability. DdFXN is monomeric and compact. The analysis of the secondary structure content, calculated using the far-UV CD spectra, was compatible with the data expected for the FXN fold, and near-UV CD spectra were compatible with the data corresponding to a folded protein. In addition, Tryptophan fluorescence indicated that the emission occurs from an apolar environment. However, the conformation of DdFXN is significantly less stable than that of the human FXN, (4.0 vs. 9.0 kcal mol-1, respectively). Based on a sequence analysis and structural models of DdFXN, we investigated key residues involved in the interaction of DdFXN with the supercomplex and the effect of point mutations on the energetics of the DdFXN tertiary structure. More than 10 residues involved in Friedreich's Ataxia are conserved between the human and DdFXN forms, and a good correlation between mutational effect on the energetics of both proteins were found, suggesting the existence of similar sequence/function/stability relationships. Finally, we integrated this information in an evolutionary context which highlights particular variation patterns between amoeba and humans that may reflect a functional importance of specific protein positions. Moreover, the complete pathway obtained forms a piece of evidence in favor of the hypothesis of a shared and highly conserved [Fe-S] assembly machinery between Human and D. discoideum.
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Affiliation(s)
- Justo Olmos
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
| | - María Florencia Pignataro
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
| | - Ana Belén Benítez dos Santos
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
| | - Mauro Bringas
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE CONICET), Buenos Aires C1428EGA, Argentina;
| | - Sebastián Klinke
- Fundación Instituto Leloir, IIBBA-CONICET, and Plataforma Argentina de Biología Estructural y Metabolómica PLABEM, Av. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina;
| | - Laura Kamenetzky
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
- IMPaM, CONICET, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires C1121ABG, Argentina
| | - Francisco Velazquez
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN)—(UBA/CONICET), Buenos Aires C1428EGA, Argentina
| | - Javier Santos
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
- Consejo Nacional de Investigaciones Científicas y Técnicas, Rivadavia 1917, Buenos Aires C1033AAJ, Argentina
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina
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10
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Puglisi R, Boeri Erba E, Pastore A. A Guide to Native Mass Spectrometry to determine complex interactomes of molecular machines. FEBS J 2020; 287:2428-2439. [PMID: 32142206 PMCID: PMC8647915 DOI: 10.1111/febs.15281] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 02/01/2020] [Accepted: 03/04/2020] [Indexed: 01/17/2023]
Abstract
Native mass spectrometry is an emerging technique in biology that gives the possibility to study noncovalently bound complexes with high sensitivity and accuracy. It thus allows the characterization of macromolecular assemblies, assessing their mass and stoichiometries and mapping the interacting surfaces. In this review, we discuss the application of native mass spectrometry to dynamic molecular machines based on multiple weak interactions. In the study of these machines, it is crucial to understand which and under which conditions various complexes form at any time point. We focus on the specific example of the iron-sulfur cluster biogenesis machine because this is an archetype of a dynamic machine that requires very specific and demanding experimental conditions, such as anaerobicity and the need of retaining the fold of marginally folded proteins. We describe the advantages, challenges and current limitations of the technique by providing examples from our own experience and suggesting possible future solutions.
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Affiliation(s)
- Rita Puglisi
- UK Dementia Research Institute at the Wohl Institute of King’s College LondonUK
| | | | - Annalisa Pastore
- UK Dementia Research Institute at the Wohl Institute of King’s College LondonUK
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11
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Tanaka N, Yuda E, Fujishiro T, Hirabayashi K, Wada K, Takahashi Y. Identification of IscU residues critical for de novo iron-sulfur cluster assembly. Mol Microbiol 2019; 112:1769-1783. [PMID: 31532036 DOI: 10.1111/mmi.14392] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2019] [Indexed: 01/16/2023]
Abstract
IscU is a central component of the ISC machinery and serves as a scaffold for the de novo assembly of iron-sulfur (Fe-S) clusters prior to their delivery to target apo-Fe-S proteins. However, the molecular mechanism is not yet fully understood. In this study, we have conducted mutational analysis of E. coli IscU using the recently developed genetic complementation system of a mutant that can survive without Fe-S clusters. The Fe-S cluster ligands (C37, C63, H105, C106) and the proximal D39 and K103 residues are essential for in vivo function of IscU and could not be substituted with any other amino acids. Furthermore, we found that substitution of Y3, a strictly conserved residue among IscU homologs, abolished in vivo functions. Surprisingly, a second-site suppressor mutation in IscS (A349V) reverted the defect caused by IscU Y3 substitutions. Biochemical analysis revealed that IscU Y3 was crucial for functional interaction with IscS and sulfur transfer between the two proteins. Our findings suggest that the critical role of IscU Y3 is linked to the conformational dynamics of the flexible loop of IscS, which is required for the ingenious sulfur transfer to IscU.
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Affiliation(s)
- Naoyuki Tanaka
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Eiki Yuda
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Takashi Fujishiro
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Kei Hirabayashi
- Department of Medical Sciences, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Kei Wada
- Department of Medical Sciences, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Yasuhiro Takahashi
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
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12
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Lee YM, Grauffel C, Chen T, Sargsyan K, Lim C. Factors Governing the Different Functions of Zn2+-Sites with Identical Ligands in Proteins. J Chem Inf Model 2019; 59:3946-3954. [DOI: 10.1021/acs.jcim.9b00617] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yu-Ming Lee
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Cédric Grauffel
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Ting Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Karen Sargsyan
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Carmay Lim
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu 300 Taiwan
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13
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Mons C, Botzanowski T, Nikolaev A, Hellwig P, Cianférani S, Lescop E, Bouton C, Golinelli-Cohen MP. The H2O2-Resistant Fe–S Redox Switch MitoNEET Acts as a pH Sensor To Repair Stress-Damaged Fe–S Protein. Biochemistry 2018; 57:5616-5628. [DOI: 10.1021/acs.biochem.8b00777] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Cécile Mons
- Institut de Chimie
des Substances Naturelles, CNRS UPR 2301, Univ Paris-Sud, Université
Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Thomas Botzanowski
- Laboratoire de
Spectrométrie de Masse BioOrganique, Université de Strasbourg,
CNRS, IPHC UMR 7178, 67000 Strasbourg, France
| | - Anton Nikolaev
- Laboratoire de Bioélectrochimie
et Spectroscopie, UMR 7140, Chimie de la Matière Complexe,
Université de Strasbourg-CNRS, 1 rue Blaise Pascal, 67000 Strasbourg, France
| | - Petra Hellwig
- Laboratoire de Bioélectrochimie
et Spectroscopie, UMR 7140, Chimie de la Matière Complexe,
Université de Strasbourg-CNRS, 1 rue Blaise Pascal, 67000 Strasbourg, France
| | - Sarah Cianférani
- Laboratoire de
Spectrométrie de Masse BioOrganique, Université de Strasbourg,
CNRS, IPHC UMR 7178, 67000 Strasbourg, France
| | - Ewen Lescop
- Institut de Chimie
des Substances Naturelles, CNRS UPR 2301, Univ Paris-Sud, Université
Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Cécile Bouton
- Institut de Chimie
des Substances Naturelles, CNRS UPR 2301, Univ Paris-Sud, Université
Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Marie-Pierre Golinelli-Cohen
- Institut de Chimie
des Substances Naturelles, CNRS UPR 2301, Univ Paris-Sud, Université
Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
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14
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Congenital sideroblastic anemia: Advances in gene mutations and pathophysiology. Gene 2018; 668:182-189. [DOI: 10.1016/j.gene.2018.05.074] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 05/18/2018] [Indexed: 01/19/2023]
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15
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Cysteine Desulfurase IscS2 Plays a Role in Oxygen Resistance in Clostridium difficile. Infect Immun 2018; 86:IAI.00326-18. [PMID: 29866903 DOI: 10.1128/iai.00326-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 05/25/2018] [Indexed: 11/20/2022] Open
Abstract
Clostridium difficile is an anaerobic, spore-forming bacterium capable of colonizing the gastrointestinal tract of humans following disruption of the normal microbiota, typically from antibiotic therapy for an unrelated infection. With approximately 500,000 confirmed infections leading to 29,000 deaths per year in the United States, C. difficile infection (CDI) is an urgent public health threat. We previously determined that C. difficile survives in up to 3% oxygen. Low levels of oxygen are present in the intestinal tract, with the higher concentrations being associated with the epithelial cell surface. Additionally, antibiotic treatment, the greatest risk factor for CDI, increases the intestinal oxygen concentration. Therefore, we hypothesized that the C. difficile genome encodes mechanisms for survival during oxidative stress. Previous data have shown that cysteine desulfurases involved in iron-sulfur cluster assembly are involved in protecting bacteria from oxidative stress. In this study, deletion of a putative cysteine desulfurase (Cd630_12790/IscS2) involved in the iron-sulfur cluster (Isc) system caused a severe growth defect in the presence of 2% oxygen. Additionally, this mutant delayed colonization in a conventional mouse model of CDI and failed to colonize in a germfree model, which has higher intestinal oxygen levels. These data imply an undefined role for this cysteine desulfurase in protecting C. difficile from low levels of oxygen in the gut.
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16
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Willemse D, Weber B, Masino L, Warren RM, Adinolfi S, Pastore A, Williams MJ. Rv1460, a SufR homologue, is a repressor of the suf operon in Mycobacterium tuberculosis. PLoS One 2018; 13:e0200145. [PMID: 29979728 PMCID: PMC6034842 DOI: 10.1371/journal.pone.0200145] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 06/20/2018] [Indexed: 11/19/2022] Open
Abstract
Iron–sulphur (Fe-S) clusters are ubiquitous co-factors which require multi-protein systems for their synthesis. In Mycobacterium tuberculosis, the Rv1460-Rv1461-Rv1462-Rv1463-csd-Rv1465-Rv1466 operon (suf operon) encodes the primary Fe-S cluster biogenesis system. The first gene in this operon, Rv1460, shares homology with the cyanobacterial SufR, which functions as a transcriptional repressor of the sufBCDS operon. Rv1460’s function in M. tuberculosis has however not been determined. In this study, we demonstrate that M. tuberculosis mutants lacking a functional Rv1460 protein are impaired for growth under standard culture conditions. Elevated expression of Rv1460 and Rv1461 was observed in the mutant, implicating Rv1460 in the regulation of the suf operon. Binding of an Fe-S cluster to purified recombinant Rv1460 was confirmed by UV-visible spectroscopy and circular dichroism. Furthermore, three conserved cysteine residues, C203, C216 and C244, proposed to provide ligands for the coordination of an Fe-S cluster, were shown to be required for the function of Rv1460 in M. tuberculosis. Rv1460 therefore seems to be functionally analogous to cyanobacterial SufR.
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Affiliation(s)
- Danicke Willemse
- DST-NRF Centre of Excellence for Biomedical Tuberculosis Research; South African Medical Research Council Centre for Tuberculosis Research; Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, South Africa
| | - Brandon Weber
- Electron Microscope Unit, University of Cape Town, Cape Town, South Africa
| | - Laura Masino
- Structural Biology Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Robin M. Warren
- DST-NRF Centre of Excellence for Biomedical Tuberculosis Research; South African Medical Research Council Centre for Tuberculosis Research; Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, South Africa
| | - Salvatore Adinolfi
- Pharmaceutical Science and Technology, University of Turin, Turin, Italy
| | - Annalisa Pastore
- Department of Basic and Clinical Neuroscience, Maurice Wohl Institute, King's College London, London, United Kingdom
| | - Monique J. Williams
- DST-NRF Centre of Excellence for Biomedical Tuberculosis Research; South African Medical Research Council Centre for Tuberculosis Research; Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, South Africa
- * E-mail:
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17
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Abstract
Proteins undergo both cold and heat denaturation, but often cold denaturation cannot be detected because it occurs at temperatures below water freezing. Proteins undergoing detectable cold as well as heat denaturation yield a reliable curve of protein stability. Here we use bacterial IscU, an essential and ancient protein involved in iron cluster biogenesis, to show an important example of unbiased cold denaturation, based on electrostatic frustration caused by a dualism between iron–sulfur cluster binding and the presence of a functionally essential electrostatic gate. We explore the structural determinants and the universals that determine cold denaturation with the aid of a coarse grain model. Our results set a firm point in our understanding of cold denaturation and give us general rules to induce and predict protein cold denaturation. The conflict between ligand binding and stability hints at the importance of the structure–function dualism in protein evolution.
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18
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Roy P, Bauman MA, Almutairi HH, Jayawardhana WG, Johnson NM, Torelli AT. Comparison of the Response of Bacterial IscU and SufU to Zn 2+ and Select Transition-Metal Ions. ACS Chem Biol 2018; 13:591-599. [PMID: 29210568 DOI: 10.1021/acschembio.7b00442] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
IscU, the central scaffold protein in the bacterial ISC iron-sulfur (Fe-S) cluster biosynthesis system, has long been recognized to bind a Zn2+ ion at its active site. While initially regarded as an artifact, Zn2+ binding has been shown to induce stabilization of the IscU structure that may mimic a state biologically relevant to IscU's role in Fe-S cluster biosynthesis. More recent studies have revealed that SufU, a homologous protein involved in Fe-S cluster biosynthesis in Gram-positive bacteria, also binds a Zn2+ ion with structural implications. Given the widespread occurrence of the "IscU-like" protein fold, particularly among Fe-S cluster biosynthesis systems, an interesting question arises as to whether Zn2+ ion binding and the resulting structural alterations are common properties in IscU-like proteins. Interactions between IscU and specific metal ions are investigated and compared side-by-side with those of SufU from a representative Gram-positive bacterium in the phylum Firmicutes. These studies were extended with additional transition metal ions chosen to investigate the influence of coordination geometry on selectivity for binding at the active sites of IscU and SufU. Monitoring and comparing the conformational behavior and stabilization afforded by different transition metal ions upon IscU and SufU revealed similarities between the two proteins and suggest that metal-dependent conformational transitions may be characteristic of U-type proteins involved in Fe-S cluster biosynthesis.
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Affiliation(s)
- Poorna Roy
- Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Mariia A. Bauman
- Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Hayfa Habes Almutairi
- Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Walimuni Geethamala Jayawardhana
- Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Nathan M. Johnson
- Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Andrew T. Torelli
- Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
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19
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20
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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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21
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Fantini M, Malinverni D, De Los Rios P, Pastore A. New Techniques for Ancient Proteins: Direct Coupling Analysis Applied on Proteins Involved in Iron Sulfur Cluster Biogenesis. Front Mol Biosci 2017; 4:40. [PMID: 28664160 PMCID: PMC5471300 DOI: 10.3389/fmolb.2017.00040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 05/24/2017] [Indexed: 12/01/2022] Open
Abstract
Direct coupling analysis (DCA) is a powerful statistical inference tool used to study protein evolution. It was introduced to predict protein folds and protein-protein interactions, and has also been applied to the prediction of entire interactomes. Here, we have used it to analyze three proteins of the iron-sulfur biogenesis machine, an essential metabolic pathway conserved in all organisms. We show that DCA can correctly reproduce structural features of the CyaY/frataxin family (a protein involved in the human disease Friedreich's ataxia) despite being based on the relatively small number of sequences allowed by its genomic distribution. This result gives us confidence in the method. Its application to the iron-sulfur cluster scaffold protein IscU, which has been suggested to function both as an ordered and a disordered form, allows us to distinguish evolutionary traces of the structured species, suggesting that, if present in the cell, the disordered form has not left evolutionary imprinting. We observe instead, for the first time, direct indications of how the protein can dimerize head-to-head and bind 4Fe4S clusters. Analysis of the alternative scaffold protein IscA provides strong support to a coordination of the cluster by a dimeric form rather than a tetramer, as previously suggested. Our analysis also suggests the presence in solution of a mixture of monomeric and dimeric species, and guides us to the prevalent one. Finally, we used DCA to analyze interactions between some of these proteins, and discuss the potentials and limitations of the method.
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Affiliation(s)
- Marco Fantini
- BioSNS, Faculty of Mathematical and Natural Sciences, Scuola Normale SuperiorePisa, Italy
| | - Duccio Malinverni
- Institute of Physics, School of Basic Sciences, and Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de LausanneLausanne, Switzerland
| | - Paolo De Los Rios
- Institute of Physics, School of Basic Sciences, and Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de LausanneLausanne, Switzerland
| | - Annalisa Pastore
- Maurice Wohl Institute, King's CollegeLondon, United Kingdom.,Molecular Medicine Department, University of PaviaPavia, Italy
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22
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Fidai I, Wachnowsky C, Cowan JA. Glutathione-complexed [2Fe-2S] clusters function in Fe-S cluster storage and trafficking. J Biol Inorg Chem 2016; 21:887-901. [PMID: 27590019 DOI: 10.1007/s00775-016-1387-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/12/2016] [Indexed: 12/19/2022]
Abstract
Glutathione-coordinated [2Fe-2S] complex is a non-protein-bound [2Fe-2S] cluster that is capable of reconstituting the human iron-sulfur cluster scaffold protein IscU. This complex demonstrates physiologically relevant solution chemistry and is a viable substrate for iron-sulfur cluster transport by Atm1p exporter protein. Herein, we report on some of the possible functional and physiological roles for this novel [2Fe-2S](GS4) complex in iron-sulfur cluster biosynthesis and quantitatively characterize its role in the broader network of Fe-S cluster transfer reactions. UV-vis and circular dichroism spectroscopy have been used in kinetic studies to determine second-order rate constants for [2Fe-2S] cluster transfer from [2Fe-2S](GS4) complex to acceptor proteins, such as human IscU, Schizosaccharomyces pombe Isa1, human and yeast glutaredoxins (human Grx2 and Saccharomyces cerevisiae Grx3), and human ferredoxins. Second-order rate constants for cluster extraction from these holo proteins were also determined by varying the concentration of glutathione, and a likely common mechanism for cluster uptake was determined by kinetic analysis. The results indicate that the [2Fe-2S](GS4) complex is stable under physiological conditions, and demonstrates reversible cluster exchange with a wide range of Fe-S cluster proteins, thereby supporting a possible physiological role for such centers.
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Affiliation(s)
- Insiya Fidai
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA.,The Biophysics Graduate Program, The Ohio State University, Columbus, USA
| | - Christine Wachnowsky
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA.,The Ohio State Biochemistry Program, The Ohio State University, Columbus, USA
| | - J A Cowan
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA. .,The Biophysics Graduate Program, The Ohio State University, Columbus, USA. .,The Ohio State Biochemistry Program, The Ohio State University, Columbus, USA.
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23
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di Maio D, Chandramouli B, Yan R, Brancato G, Pastore A. Understanding the role of dynamics in the iron sulfur cluster molecular machine. Biochim Biophys Acta Gen Subj 2016; 1861:3154-3163. [PMID: 27474202 PMCID: PMC5176006 DOI: 10.1016/j.bbagen.2016.07.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Revised: 07/17/2016] [Accepted: 07/24/2016] [Indexed: 11/17/2022]
Abstract
BACKGROUND The bacterial proteins IscS, IscU and CyaY, the bacterial orthologue of frataxin, play an essential role in the biological machine that assembles the prosthetic FeS cluster groups on proteins. They form functionally binary and ternary complexes both in vivo and in vitro. Yet, the mechanism by which they work remains unclear. METHODS We carried out extensive molecular dynamics simulations to understand the nature of their interactions and the role of dynamics starting from the crystal structure of a IscS-IscU complex and the experimentally-based model of a ternary IscS-IscU-CyaY complex and used nuclear magnetic resonance to experimentally test the interface. RESULTS We show that, while being firmly anchored to IscS, IscU has a pivotal motion around the interface. Our results also describe how the catalytic loop of IscS can flip conformation to allow FeS cluster assembly. This motion is hampered in the ternary complex explaining its inhibitory properties in cluster formation. CONCLUSIONS We conclude that the observed 'fluid' IscS-IscU interface provides the binary complex with a functional adaptability exploited in partner recognition and unravels the molecular determinants of the reported inhibitory action of CyaY in the IscS-IscU-CyaY complex explained in terms of the hampering effect on specific IscU-IscS movements. GENERAL SIGNIFICANCE Our study provides the first mechanistic basis to explain how the IscS-IscU complex selects its binding partners and supports the inhibitory role of CyaY in the ternary complex.
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Affiliation(s)
- Danilo di Maio
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy; Istituto Nazionale di Fisica Nucleare (INFN) sezione di Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, Italy
| | - Balasubramanian Chandramouli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy; Istituto Nazionale di Fisica Nucleare (INFN) sezione di Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, Italy
| | - Robert Yan
- Department of Neuroscience, Wohl Institute, King's College London, Denmark Hill Campus, London SE5, UK
| | - Giuseppe Brancato
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy; Istituto Nazionale di Fisica Nucleare (INFN) sezione di Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, Italy.
| | - Annalisa Pastore
- Department of Neuroscience, Wohl Institute, King's College London, Denmark Hill Campus, London SE5, UK; Immunologia Patologia Generale Department, University of Pavia, Via Ferrata, 9, 27100 Pavia, Italy.
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24
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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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Holt W, Fazeli A. Sperm selection in the female mammalian reproductive tract. Focus on the oviduct: Hypotheses, mechanisms, and new opportunities. Theriogenology 2016; 85:105-12. [DOI: 10.1016/j.theriogenology.2015.07.019] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 07/13/2015] [Accepted: 07/16/2015] [Indexed: 12/19/2022]
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