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Falb N, Patil G, Furtmüller PG, Gabler T, Hofbauer S. Structural aspects of enzymes involved in prokaryotic Gram-positive heme biosynthesis. Comput Struct Biotechnol J 2023; 21:3933-3945. [PMID: 37593721 PMCID: PMC10427985 DOI: 10.1016/j.csbj.2023.07.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/19/2023] [Accepted: 07/19/2023] [Indexed: 08/19/2023] Open
Abstract
The coproporphyrin dependent heme biosynthesis pathway is almost exclusively utilized by Gram-positive bacteria. This fact makes it a worthwhile topic for basic research, since a fundamental understanding of a metabolic pathway is necessary to translate the focus towards medical biotechnology, which is very relevant in this specific case, considering the need for new antibiotic targets to counteract the pathogenicity of Gram-positive superbugs. Over the years a lot of structural data on the set of enzymes acting in Gram-positive heme biosynthesis has accumulated in the Protein Database (www.pdb.org). One major challenge is to filter and analyze all available structural information in sufficient detail in order to be helpful and to draw conclusions. Here we pursued to give a holistic overview of structural information on enzymes involved in the coproporphyrin dependent heme biosynthesis pathway. There are many aspects to be extracted from experimentally determined structures regarding the reaction mechanisms, where the smallest variation of the position of an amino acid residue might be important, but also on a larger level regarding protein-protein interactions, where the focus has to be on surface characteristics and subunit (secondary) structural elements and oligomerization. This review delivers a status quo, highlights still missing information, and formulates future research endeavors in order to better understand prokaryotic heme biosynthesis.
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Affiliation(s)
- Nikolaus Falb
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Biochemistry, Muthgasse 18, A-1190 Vienna, Austria
| | - Gaurav Patil
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Biochemistry, Muthgasse 18, A-1190 Vienna, Austria
| | - Paul G. Furtmüller
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Biochemistry, Muthgasse 18, A-1190 Vienna, Austria
| | - Thomas Gabler
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Biochemistry, Muthgasse 18, A-1190 Vienna, Austria
| | - Stefan Hofbauer
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Biochemistry, Muthgasse 18, A-1190 Vienna, Austria
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2
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Morante S, Botticelli S, Chiaraluce R, Consalvi V, La Penna G, Novak L, Pasquo A, Petrosino M, Proux O, Rossi G, Salina G, Stellato F. Metal Ion Binding in Wild-Type and Mutated Frataxin: A Stability Study. Front Mol Biosci 2022; 9:878017. [PMID: 35712353 PMCID: PMC9195147 DOI: 10.3389/fmolb.2022.878017] [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: 02/17/2022] [Accepted: 04/12/2022] [Indexed: 11/13/2022] Open
Abstract
This work studies the stability of wild-type frataxin and some of its variants found in cancer tissues upon Co2+ binding. Although the physiologically involved metal ion in the frataxin enzymatic activity is Fe2+, as it is customarily done, Co2+ is most often used in experiments because Fe2+ is extremely unstable owing to the fast oxidation reaction Fe2+ → Fe3+. Protein stability is monitored following the conformational changes induced by Co2+ binding as measured by circular dichroism, fluorescence spectroscopy, and melting temperature measurements. The stability ranking among the wild-type frataxin and its variants obtained in this way is confirmed by a detailed comparative analysis of the XAS spectra of the metal-protein complex at the Co K-edge. In particular, a fit to the EXAFS region of the spectrum allows positively identifying the frataxin acidic ridge as the most likely location of the metal-binding sites. Furthermore, we can explain the surprising feature emerging from a detailed analysis of the XANES region of the spectrum, showing that the longer 81-210 frataxin fragment has a smaller propensity for Co2+ binding than the shorter 90-210 one. This fact is explained by the peculiar role of the N-terminal disordered tail in modulating the protein ability to interact with the metal.
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Affiliation(s)
- S. Morante
- Dipartimento di Fisica, Universitá di Roma Tor Vergata, Rome, Italy
- INFN, Sezione di Roma Tor Vergata, Rome, Italy
- *Correspondence: S. Morante ,
| | - S. Botticelli
- Dipartimento di Fisica, Universitá di Roma Tor Vergata, Rome, Italy
- INFN, Sezione di Roma Tor Vergata, Rome, Italy
| | - R. Chiaraluce
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Sapienza Universitá di Roma, Rome, Italy
| | - V. Consalvi
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Sapienza Universitá di Roma, Rome, Italy
| | - G. La Penna
- INFN, Sezione di Roma Tor Vergata, Rome, Italy
- CNR—Istituto di Chimica dei Composti Organometallici, Firenze, Italy
| | - L. Novak
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Sapienza Universitá di Roma, Rome, Italy
| | - A. Pasquo
- ENEA CR Frascati, Diagnostics and Metrology Laboratory FSN-TECFIS-DIM, Frascati, Italy
| | - M. Petrosino
- Chair of Pharmacology, Section of Medicine, University of Fribourg, Fribourg, Switzerland
| | - O. Proux
- Observatoire des Sciences de L’Univers de Grenoble, UAR 832 CNRS, Université Grenoble Alpes, Grenoble, France
| | - G. Rossi
- Dipartimento di Fisica, Universitá di Roma Tor Vergata, Rome, Italy
- INFN, Sezione di Roma Tor Vergata, Rome, Italy
- Museo Storico della Fisica e Centro Studi e Ricerche E. Fermi, Roma, Italy
| | - G. Salina
- INFN, Sezione di Roma Tor Vergata, Rome, Italy
| | - F. Stellato
- Dipartimento di Fisica, Universitá di Roma Tor Vergata, Rome, Italy
- INFN, Sezione di Roma Tor Vergata, Rome, Italy
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3
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Botticelli S, La Penna G, Nobili G, Rossi G, Stellato F, Morante S. Modelling Protein Plasticity: The Example of Frataxin and Its Variants. Molecules 2022; 27:1955. [PMID: 35335316 PMCID: PMC8950120 DOI: 10.3390/molecules27061955] [Citation(s) in RCA: 1] [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: 01/31/2022] [Revised: 03/07/2022] [Accepted: 03/13/2022] [Indexed: 12/20/2022] Open
Abstract
Frataxin (FXN) is a protein involved in storage and delivery of iron in the mitochondria. Single-point mutations in the FXN gene lead to reduced production of functional frataxin, with the consequent dyshomeostasis of iron. FXN variants are at the basis of neurological impairment (the Friedreich's ataxia) and several types of cancer. By using altruistic metadynamics in conjunction with the maximal constrained entropy principle, we estimate the change of free energy in the protein unfolding of frataxin and of some of its pathological mutants. The sampled configurations highlight differences between the wild-type and mutated sequences in the stability of the folded state. In partial agreement with thermodynamic experiments, where most of the analyzed variants are characterized by lower thermal stability compared to wild type, the D104G variant is found with a stability comparable to the wild-type sequence and a lower water-accessible surface area. These observations, obtained with the new approach we propose in our work, point to a functional switch, affected by single-point mutations, of frataxin from iron storage to iron release. The method is suitable to investigate wide structural changes in proteins in general, after a proper tuning of the chosen collective variable used to perform the transition.
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Affiliation(s)
- Simone Botticelli
- Dipartimento di Fisica, Università di Roma Tor Vergata and Sezione di Roma Tor Vergata, INFN, Via della Ricerca Scientifica 1, I-00133 Roma, Italy; (S.B.); (G.N.); (G.R.); (F.S.); (S.M.)
| | - Giovanni La Penna
- Dipartimento di Fisica, Università di Roma Tor Vergata and Sezione di Roma Tor Vergata, INFN, Via della Ricerca Scientifica 1, I-00133 Roma, Italy; (S.B.); (G.N.); (G.R.); (F.S.); (S.M.)
- Istituto di Chimica dei Composti Organometallici, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, I-50019 Firenze, Italy
| | - Germano Nobili
- Dipartimento di Fisica, Università di Roma Tor Vergata and Sezione di Roma Tor Vergata, INFN, Via della Ricerca Scientifica 1, I-00133 Roma, Italy; (S.B.); (G.N.); (G.R.); (F.S.); (S.M.)
| | - Giancarlo Rossi
- Dipartimento di Fisica, Università di Roma Tor Vergata and Sezione di Roma Tor Vergata, INFN, Via della Ricerca Scientifica 1, I-00133 Roma, Italy; (S.B.); (G.N.); (G.R.); (F.S.); (S.M.)
- Centro Fermi—Museo Storico della Fisica e Centro Studi e Ricerche E. Fermi, I-00184 Roma, Italy
| | - Francesco Stellato
- Dipartimento di Fisica, Università di Roma Tor Vergata and Sezione di Roma Tor Vergata, INFN, Via della Ricerca Scientifica 1, I-00133 Roma, Italy; (S.B.); (G.N.); (G.R.); (F.S.); (S.M.)
- Centro Fermi—Museo Storico della Fisica e Centro Studi e Ricerche E. Fermi, I-00184 Roma, Italy
| | - Silvia Morante
- Dipartimento di Fisica, Università di Roma Tor Vergata and Sezione di Roma Tor Vergata, INFN, Via della Ricerca Scientifica 1, I-00133 Roma, Italy; (S.B.); (G.N.); (G.R.); (F.S.); (S.M.)
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Monfort B, Want K, Gervason S, D’Autréaux B. Recent Advances in the Elucidation of Frataxin Biochemical Function Open Novel Perspectives for the Treatment of Friedreich’s Ataxia. Front Neurosci 2022; 16:838335. [PMID: 35310092 PMCID: PMC8924461 DOI: 10.3389/fnins.2022.838335] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/28/2022] [Indexed: 12/25/2022] Open
Abstract
Friedreich’s ataxia (FRDA) is the most prevalent autosomic recessive ataxia and is associated with a severe cardiac hypertrophy and less frequently diabetes. It is caused by mutations in the gene encoding frataxin (FXN), a small mitochondrial protein. The primary consequence is a defective expression of FXN, with basal protein levels decreased by 70–98%, which foremost affects the cerebellum, dorsal root ganglia, heart and liver. FXN is a mitochondrial protein involved in iron metabolism but its exact function has remained elusive and highly debated since its discovery. At the cellular level, FRDA is characterized by a general deficit in the biosynthesis of iron-sulfur (Fe-S) clusters and heme, iron accumulation and deposition in mitochondria, and sensitivity to oxidative stress. Based on these phenotypes and the proposed ability of FXN to bind iron, a role as an iron storage protein providing iron for Fe-S cluster and heme biosynthesis was initially proposed. However, this model was challenged by several other studies and it is now widely accepted that FXN functions primarily in Fe-S cluster biosynthesis, with iron accumulation, heme deficiency and oxidative stress sensitivity appearing later on as secondary defects. Nonetheless, the biochemical function of FXN in Fe-S cluster biosynthesis is still debated. Several roles have been proposed for FXN: iron chaperone, gate-keeper of detrimental Fe-S cluster biosynthesis, sulfide production stimulator and sulfur transfer accelerator. A picture is now emerging which points toward a unique function of FXN as an accelerator of a key step of sulfur transfer between two components of the Fe-S cluster biosynthetic complex. These findings should foster the development of new strategies for the treatment of FRDA. We will review here the latest discoveries on the biochemical function of frataxin and the implication for a potential therapeutic treatment of FRDA.
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Tamarit J, Britti E, Delaspre F, Medina-Carbonero M, Sanz-Alcázar A, Cabiscol E, Ros J. Mitochondrial iron and calcium homeostasis in Friedreich ataxia. IUBMB Life 2021; 73:543-553. [PMID: 33675183 DOI: 10.1002/iub.2457] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/08/2021] [Accepted: 02/08/2021] [Indexed: 12/13/2022]
Abstract
Friedreich Ataxia is a neuro-cardiodegenerative disease caused by the deficiency of frataxin, a mitochondrial protein. Many evidences indicate that frataxin deficiency causes an unbalance of iron homeostasis. Nevertheless, in the last decade many results also highlighted the importance of calcium unbalance in the deleterious downstream effects caused by frataxin deficiency. In this review, the role of these two metals has been gathered to give a whole view of how iron and calcium dyshomeostasys impacts on cellular functions and, as a result, which strategies can be followed to find an effective therapy for the disease.
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Affiliation(s)
- Jordi Tamarit
- Dept. Ciències Mèdiques Bàsiques, Universitat de Lleida, IRBLleida, Lleida, Spain
| | - Elena Britti
- Dept. Ciències Mèdiques Bàsiques, Universitat de Lleida, IRBLleida, Lleida, Spain
| | - Fabien Delaspre
- Dept. Ciències Mèdiques Bàsiques, Universitat de Lleida, IRBLleida, Lleida, Spain
| | | | - Arabela Sanz-Alcázar
- Dept. Ciències Mèdiques Bàsiques, Universitat de Lleida, IRBLleida, Lleida, Spain
| | - Elisa Cabiscol
- Dept. Ciències Mèdiques Bàsiques, Universitat de Lleida, IRBLleida, Lleida, Spain
| | - Joaquim Ros
- Dept. Ciències Mèdiques Bàsiques, Universitat de Lleida, IRBLleida, Lleida, Spain
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Schiavi A, Strappazzon F, Ventura N. Mitophagy and iron: two actors sharing the stage in age-associated neuronal pathologies. Mech Ageing Dev 2020; 188:111252. [PMID: 32330468 DOI: 10.1016/j.mad.2020.111252] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 12/12/2022]
Abstract
Aging is characterized by the deterioration of different cellular and organismal structures and functions. A typical hallmark of the aging process is the accumulation of dysfunctional mitochondria and excess iron, leading to a vicious cycle that promotes cell and tissue damage, which ultimately contribute to organismal aging. Accordingly, altered mitochondrial quality control pathways such as mitochondrial autophagy (mitophagy) as well as altered iron homeostasis, with consequent iron overload, can accelerate the aging process and the development and progression of different age-associated disorders. In this review we first briefly introduce the aging process and summarize molecular mechanisms regulating mitophagy and iron homeostasis. We then provide an overview on how dysfunction of these two processes impact on aging and age-associated neurodegenerative disorders with a focus on Alzheimer's disease, Parkinson's disease and Amyotrophic Lateral Sclerosis. Finally, we summarize some recent evidence showing mechanistic links between iron metabolism and mitophagy and speculate on how regulating the crosstalk between the two processes may provide protective effects against aging and age-associated neuronal pathologies.
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Affiliation(s)
- Alfonso Schiavi
- Institute of Clinical Chemistry and Laboratory Diagnostic, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany; IUF- Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | | | - Natascia Ventura
- Institute of Clinical Chemistry and Laboratory Diagnostic, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany; IUF- Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany.
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7
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Abstract
Friedreich's ataxia (FRDA) is a degenerative disease that affects both the central and the peripheral nervous systems and non-neural tissues including, mainly, heart, and endocrine pancreas. It is an autosomal recessive disease caused by a GAA triplet-repeat localized within an Alu sequence element in intron 1 of frataxin (FXN) gene, which encodes a mitochondrial protein FXN. This protein is essential for mitochondrial function by the involvement of iron-sulfur cluster biogenesis. The effects of its deficiency also include disruption of cellular, particularly mitochondrial, iron homeostasis, i.e., relatively more iron accumulated in mitochondria and less iron presented in cytosol. Though iron toxicity is commonly thought to be mediated via Fenton reaction, oxidative stress seems not to be the main problem to result in detrimental effects on cell survival, particularly neuron survival. Therefore, the basic research on FXN function is urgently demanded to understand the disease. This chapter focuses on the outcome of FXN expression, regulation, and function in cellular or animal models of FRDA and on iron pathophysiology in the affected tissues. Finally, therapeutic strategies based on the control of iron toxicity and iron cellular redistribution are considered. The combination of multiple therapeutic targets including iron, oxidative stress, mitochondrial function, and FXN regulation is also proposed.
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Affiliation(s)
- Kuanyu Li
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, People's Republic of China.
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8
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Ward DM, Chen OS, Li L, Kaplan J, Bhuiyan SA, Natarajan SK, Bard M, Cox JE. Altered sterol metabolism in budding yeast affects mitochondrial iron-sulfur (Fe-S) cluster synthesis. J Biol Chem 2018; 293:10782-10795. [PMID: 29773647 DOI: 10.1074/jbc.ra118.001781] [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: 01/05/2018] [Revised: 05/11/2018] [Indexed: 01/05/2023] Open
Abstract
Ergosterol synthesis is essential for cellular growth and viability of the budding yeast Saccharomyces cerevisiae, and intracellular sterol distribution and homeostasis are therefore highly regulated in this species. Erg25 is an iron-containing C4-methyl sterol oxidase that contributes to the conversion of 4,4-dimethylzymosterol to zymosterol, a precursor of ergosterol. The ERG29 gene encodes an endoplasmic reticulum (ER)-associated protein, and here we identified a role for Erg29 in the methyl sterol oxidase step of ergosterol synthesis. ERG29 deletion resulted in lethality in respiring cells, but respiration-incompetent (Rho- or Rho0) cells survived, suggesting that Erg29 loss leads to accumulation of oxidized sterol metabolites that affect cell viability. Down-regulation of ERG29 expression in Δerg29 cells indeed led to accumulation of methyl sterol metabolites, resulting in increased mitochondrial oxidants and a decreased ability of mitochondria to synthesize iron-sulfur (Fe-S) clusters due to reduced levels of Yfh1, the mammalian frataxin homolog, which is involved in mitochondrial iron metabolism. Using a high-copy genomic library, we identified suppressor genes that permitted growth of Δerg29 cells on respiratory substrates, and these included genes encoding the mitochondrial proteins Yfh1, Mmt1, Mmt2, and Pet20, which reversed all phenotypes associated with loss of ERG29 Of note, loss of Erg25 also resulted in accumulation of methyl sterol metabolites and also increased mitochondrial oxidants and degradation of Yfh1. We propose that accumulation of toxic intermediates of the methyl sterol oxidase reaction increases mitochondrial oxidants, which affect Yfh1 protein stability. These results indicate an interaction between sterols generated by ER proteins and mitochondrial iron metabolism.
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Affiliation(s)
- Diane M Ward
- From the Department of Pathology, Division of Microbiology and Immunology, and
| | - Opal S Chen
- the DNA Sequencing Core, University of Utah School of Medicine, Salt Lake City, Utah 84132
| | - Liangtao Li
- From the Department of Pathology, Division of Microbiology and Immunology, and
| | - Jerry Kaplan
- From the Department of Pathology, Division of Microbiology and Immunology, and
| | - Shah Alam Bhuiyan
- the Department of Biology, Indiana University-Purdue University, Indianapolis, Indiana 46202, and
| | - Selvamuthu K Natarajan
- the Department of Biology, Indiana University-Purdue University, Indianapolis, Indiana 46202, and
| | - Martin Bard
- the Department of Biology, Indiana University-Purdue University, Indianapolis, Indiana 46202, and
| | - James E Cox
- the Department of Biochemistry and.,Metabolomics Core Research Facility, University of Utah School of Medicine, Salt Lake City, Utah 84112
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Ahlgren EC, Fekry M, Wiemann M, Söderberg CA, Bernfur K, Gakh O, Rasmussen M, Højrup P, Emanuelsson C, Isaya G, Al-Karadaghi S. Iron-induced oligomerization of human FXN81-210 and bacterial CyaY frataxin and the effect of iron chelators. PLoS One 2017; 12:e0188937. [PMID: 29200434 PMCID: PMC5714350 DOI: 10.1371/journal.pone.0188937] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 11/15/2017] [Indexed: 12/12/2022] Open
Abstract
Patients suffering from the progressive neurodegenerative disease Friedreich's ataxia have reduced expression levels of the protein frataxin. Three major isoforms of human frataxin have been identified, FXN42-210, FXN56-210 and FXN81-210, of which FXN81-210 is considered to be the mature form. Both long forms, FXN42-210 and FXN56-210, have been shown to spontaneously form oligomeric particles stabilized by the extended N-terminal sequence. The short variant FXN81-210, on other hand, has only been observed in the monomeric state. However, a highly homologous E. coli frataxin CyaY, which also lacks an N-terminal extension, has been shown to oligomerize in the presence of iron. To explore the mechanisms of stabilization of short variant frataxin oligomers we compare here the effect of iron on the oligomerization of CyaY and FXN81-210. Using dynamic light scattering, small-angle X-ray scattering, electron microscopy (EM) and cross linking mass spectrometry (MS), we show that at aerobic conditions in the presence of iron both FXN81-210 and CyaY form oligomers. However, while CyaY oligomers are stable over time, FXN81-210 oligomers are unstable and dissociate into monomers after about 24 h. EM and MS studies suggest that within the oligomers FXN81-210 and CyaY monomers are packed in a head-to-tail fashion in ring-shaped structures with potential iron-binding sites located at the interface between monomers. The higher stability of CyaY oligomers can be explained by a higher number of acidic residues at the interface between monomers, which may result in a more stable iron binding. We also show that CyaY oligomers may be dissociated by ferric iron chelators deferiprone and DFO, as well as by the ferrous iron chelator BIPY. Surprisingly, deferiprone and DFO stimulate FXN81-210 oligomerization, while BIPY does not show any effect on oligomerization in this case. The results suggest that FXN81-210 oligomerization is primarily driven by ferric iron, while both ferric and ferrous iron participate in CyaY oligomer stabilization. Analysis of the amino acid sequences of bacterial and eukaryotic frataxins suggests that variations in the position of the acidic residues in helix 1, β-strand 1 and the loop between them may control the mode of frataxin oligomerization.
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Affiliation(s)
- Eva-Christina Ahlgren
- Center for Molecular Protein Science, Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - Mostafa Fekry
- Center for Molecular Protein Science, Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
- Biophysics Department, Faculty of Science, Cairo University, Giza, Egypt
| | - Mathias Wiemann
- Center for Molecular Protein Science, Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - Christopher A. Söderberg
- Center for Molecular Protein Science, Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - Katja Bernfur
- Center for Molecular Protein Science, Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - Olex Gakh
- Departments of Pediatric and Adolescent Medicine and Biochemistry and Molecular Biology, Mayo Clinic, College of Medicine, Rochester, Minnesota, United States of America
| | - Morten Rasmussen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Peter Højrup
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Cecilia Emanuelsson
- Center for Molecular Protein Science, Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - Grazia Isaya
- Departments of Pediatric and Adolescent Medicine and Biochemistry and Molecular Biology, Mayo Clinic, College of Medicine, Rochester, Minnesota, United States of America
| | - Salam Al-Karadaghi
- Center for Molecular Protein Science, Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
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SAXS and stability studies of iron-induced oligomers of bacterial frataxin CyaY. PLoS One 2017; 12:e0184961. [PMID: 28931050 PMCID: PMC5607177 DOI: 10.1371/journal.pone.0184961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 09/04/2017] [Indexed: 01/19/2023] Open
Abstract
Frataxin is a highly conserved protein found in both prokaryotes and eukaryotes. It is involved in several central functions in cells, which include iron delivery to biochemical processes, such as heme synthesis, assembly of iron-sulfur clusters (ISC), storage of surplus iron in conditions of iron overload, and repair of ISC in aconitase. Frataxin from different organisms has been shown to undergo iron-dependent oligomerization. At least two different classes of oligomers, with different modes of oligomer packing and stabilization, have been identified. Here, we continue our efforts to explore the factors that control the oligomerization of frataxin from different organisms, and focus on E. coli frataxin CyaY. Using small-angle X-ray scattering (SAXS), we show that higher iron-to-protein ratios lead to larger oligomeric species, and that oligomerization proceeds in a linear fashion as a results of iron oxidation. Native mass spectrometry and online size-exclusion chromatography combined with SAXS show that a dimer is the most common form of CyaY in the presence of iron at atmospheric conditions. Modeling of the dimer using the SAXS data confirms the earlier proposed head-to-tail packing arrangement of monomers. This packing mode brings several conserved acidic residues into close proximity to each other, creating an environment for metal ion binding and possibly even mineralization. Together with negative-stain electron microscopy, the experiments also show that trimers, tetramers, pentamers, and presumably higher-order oligomers may exist in solution. Nano-differential scanning fluorimetry shows that the oligomers have limited stability and may easily dissociate at elevated temperatures. The factors affecting the possible oligomerization mode are discussed.
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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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12
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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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13
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Uchida T, Kobayashi N, Muneta S, Ishimori K. The Iron Chaperone Protein CyaY from Vibrio cholerae Is a Heme-Binding Protein. Biochemistry 2017; 56:2425-2434. [DOI: 10.1021/acs.biochem.6b01304] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Takeshi Uchida
- Department
of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
- Graduate
School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Noriyuki Kobayashi
- Graduate
School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Souichiro Muneta
- Graduate
School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Koichiro Ishimori
- Department
of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
- Graduate
School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan
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14
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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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15
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Söderberg C, Gillam ME, Ahlgren EC, Hunter GA, Gakh O, Isaya G, Ferreira GC, Al-Karadaghi S. The Structure of the Complex between Yeast Frataxin and Ferrochelatase: CHARACTERIZATION AND PRE-STEADY STATE REACTION OF FERROUS IRON DELIVERY AND HEME SYNTHESIS. J Biol Chem 2016; 291:11887-98. [PMID: 27026703 PMCID: PMC4882455 DOI: 10.1074/jbc.m115.701128] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 03/11/2016] [Indexed: 01/08/2023] Open
Abstract
Frataxin is a mitochondrial iron-binding protein involved in iron storage, detoxification, and delivery for iron sulfur-cluster assembly and heme biosynthesis. The ability of frataxin from different organisms to populate multiple oligomeric states in the presence of metal ions, e.g. Fe(2+) and Co(2+), led to the suggestion that different oligomers contribute to the functions of frataxin. Here we report on the complex between yeast frataxin and ferrochelatase, the terminal enzyme of heme biosynthesis. Protein-protein docking and cross-linking in combination with mass spectroscopic analysis and single-particle reconstruction from negatively stained electron microscopic images were used to verify the Yfh1-ferrochelatase interactions. The model of the complex indicates that at the 2:1 Fe(2+)-to-protein ratio, when Yfh1 populates a trimeric state, there are two interaction interfaces between frataxin and the ferrochelatase dimer. Each interaction site involves one ferrochelatase monomer and one frataxin trimer, with conserved polar and charged amino acids of the two proteins positioned at hydrogen-bonding distances from each other. One of the subunits of the Yfh1 trimer interacts extensively with one subunit of the ferrochelatase dimer, contributing to the stability of the complex, whereas another trimer subunit is positioned for Fe(2+) delivery. Single-turnover stopped-flow kinetics experiments demonstrate that increased rates of heme production result from monomers, dimers, and trimers, indicating that these forms are most efficient in delivering Fe(2+) to ferrochelatase and sustaining porphyrin metalation. Furthermore, they support the proposal that frataxin-mediated delivery of this potentially toxic substrate overcomes formation of reactive oxygen species.
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Affiliation(s)
- Christopher Söderberg
- From the Center for Molecular Protein Science, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden
| | - Mallory E Gillam
- Department of Molecular Medicine, Morsani College of Medicine and
| | - Eva-Christina Ahlgren
- From the Center for Molecular Protein Science, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden
| | - Gregory A Hunter
- Department of Molecular Medicine, Morsani College of Medicine and
| | - Oleksandr Gakh
- the Departments of Pediatric and Adolescent Medicine and Biochemistry and Molecular Biology, Mayo Clinic, College of Medicine, Rochester, Minnesota 55905
| | - Grazia Isaya
- the Departments of Pediatric and Adolescent Medicine and Biochemistry and Molecular Biology, Mayo Clinic, College of Medicine, Rochester, Minnesota 55905
| | - Gloria C Ferreira
- Department of Molecular Medicine, Morsani College of Medicine and the Department of Chemistry, University of South Florida, Tampa, Florida 33612, and
| | - Salam Al-Karadaghi
- From the Center for Molecular Protein Science, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden,
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16
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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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17
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Suebpeng Y, Jetsrisuparb A, Fucharoen S, Tripatara A. Frataxin expression in reticulocytes of non-splenectomized and splenectomized patients with HbE-β-thalassaemia. Clin Biochem 2016; 49:463-466. [PMID: 26589002 DOI: 10.1016/j.clinbiochem.2015.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 11/11/2015] [Accepted: 11/12/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVES A previous report revealed that thalassaemic patients with transfusional iron overload developed oxidative stress. The aims of this study were to investigate the FXN mRNA levels in the reticulocytes of patients with HbE-beta-thalassaemia who were treated with regular transfusions, to compare the results with those from normal controls and to evaluate the relationships of the levels of FXN mRNA with malondialdehyde (MDA) and iron parameters in these patients. DESIGN AND METHODS The levels of FXN mRNA in the reticulocytes of patients (30 non-splenectomized and 30 splenectomized) and 30 normal individuals were assessed by RT-PCR. The levels of MDA and the transferrin saturations (TSs) were analysed with thiobarbituric acid-reactive substance assay and spectrometry, respectively. The level of ferritin was determined by ELISA. RESULTS The levels of FXN mRNA, MDA, ferritin, and TS in the patients were significantly higher than those in the controls. The levels of FXN mRNA, MDA, and ferritin in the non-splenectomized and splenectomized patients were significantly different, but the levels of TS in these two patient groups were comparable. The relative FXN expression in the patients was found to be correlated with the levels of MDA and ferritin but not correlated with TS. CONCLUSIONS The elevation of FXN expression in the reticulocytes of these patients seems to be linked to oxidative stress and iron status.
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Affiliation(s)
- Yollada Suebpeng
- Center for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Thailand
| | - Arunee Jetsrisuparb
- Center for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Thailand; Department of Pediatrics, Faculty of Medicine, Khon Kaen University, Thailand
| | - Supan Fucharoen
- Center for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Thailand
| | - Amporn Tripatara
- Center for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Thailand.
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18
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Zaidi A, Singh KP, Anwar S, Suman SS, Equbal A, Singh K, Dikhit MR, Bimal S, Pandey K, Das P, Ali V. Interaction of frataxin, an iron binding protein, with IscU of Fe-S clusters biogenesis pathway and its upregulation in AmpB resistant Leishmania donovani. Biochimie 2015; 115:120-35. [PMID: 26032732 DOI: 10.1016/j.biochi.2015.05.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 05/19/2015] [Indexed: 01/10/2023]
Abstract
Leishmania donovani is a unicellular protozoon parasite that causes visceral leishmaniasis (VL), which is a fatal disease if left untreated. Certain Fe-S proteins of the TCA cycle and respiratory chain have been found in the Leishmania parasite but the precise mechanisms for their biogenesis and the maturation of Fe-S clusters remains unknown. Fe-S clusters are ubiquitous cofactors of proteins that perform critical cellular functions. The clusters are biosynthesized by the mitochondrial Iron-Sulphur Cluster (ISC) machinery with core protein components that include the catalytic cysteine desulphurase IscS, the scaffold proteins IscU and IscA, and frataxin as an iron carrier/donor. However, no information regarding frataxin, its regulation, or its role in drug resistance is available for the Leishmania parasite. In this study, we characterized Ld-frataxin to investigate its role in the ISC machinery of L. donovani. We expressed and purified the recombinant Ld-frataxin protein and observed its interaction with Ld-IscU by co-purification and pull-down assay. Furthermore, we observed that the cysteine desulphurase activity of the purified Ld-IscS protein was stimulated in the presence of Ld-frataxin and Ld-IscU, particularly in the presence of iron; neither Ld-frataxin nor Ld-IscU alone had significant effects on Ld-IscS activity. Interestingly, RT-PCR and western blotting showed that Ld-frataxin is upregulated in AmpB-resistant isolates compared to sensitive strains, which may support higher Fe-S protein activity in AmpB-resistant L. donovani. Additionally, Ld-frataxin was localized in the mitochondria, as revealed by digitonin fractionation and indirect immunofluorescence. Thus, our results suggest the role of Ld-frataxin as an iron binding/carrier protein for Fe-S cluster biogenesis that physically interacts with other core components of the ISC machinery within the mitochondria.
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Affiliation(s)
- Amir Zaidi
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna 800007, India
| | - Krishn Pratap Singh
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna 800007, India
| | - Shadab Anwar
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna 800007, India
| | - Shashi S Suman
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna 800007, India
| | - Asif Equbal
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna 800007, India
| | - Kuljit Singh
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna 800007, India
| | - Manas R Dikhit
- Biomedical Informatic Centre, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna, India
| | - Sanjeeva Bimal
- Department of Immunology, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna, India
| | - Krishna Pandey
- Department of Clinical Medicine, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna, India
| | - Pradeep Das
- Department of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna, India
| | - Vahab Ali
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Agamkuan, Patna 800007, India.
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19
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Shkumatov AV, Strelkov SV. DATASW, a tool for HPLC-SAXS data analysis. ACTA ACUST UNITED AC 2015; 71:1347-50. [PMID: 26057674 DOI: 10.1107/s1399004715007154] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 04/09/2015] [Indexed: 11/10/2022]
Abstract
Small-angle X-ray scattering (SAXS) in solution is a common low-resolution method which can efficiently complement the high-resolution information obtained by crystallography or NMR. Sample monodispersity is key to reliable SAXS data interpretation and model building. Beamline setups with inline high-performance liquid chromatography (HPLC) are particularly useful for accurate profiling of heterogeneous samples. The program DATASW performs averaging of individual data frames from HPLC-SAXS experiments using a sliding window of a user-specified size, calculates overall parameters [I(0), Rg, Dmax and molecular weight] and predicts the folding state (folded/unfolded) of the sample. Applications of DATASW are illustrated for several proteins with various oligomerization behaviours recorded on different beamlines. DATASW binaries for major operating systems can be downloaded from http://datasw.sourceforge.net/.
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Affiliation(s)
- Alexander V Shkumatov
- Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Sergei V Strelkov
- Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
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20
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Kim JH, Bothe JR, Alderson TR, Markley JL. Tangled web of interactions among proteins involved in iron-sulfur cluster assembly as unraveled by NMR, SAXS, chemical crosslinking, and functional studies. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1416-28. [PMID: 25450980 DOI: 10.1016/j.bbamcr.2014.11.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 10/18/2014] [Accepted: 11/13/2014] [Indexed: 12/26/2022]
Abstract
Proteins containing iron-sulfur (Fe-S) clusters arose early in evolution and are essential to life. Organisms have evolved machinery consisting of specialized proteins that operate together to assemble Fe-S clusters efficiently so as to minimize cellular exposure to their toxic constituents: iron and sulfide ions. To date, the best studied system is the iron-sulfur cluster (isc) operon of Escherichia coli, and the eight ISC proteins it encodes. Our investigations over the past five years have identified two functional conformational states for the scaffold protein (IscU) and have shown that the other ISC proteins that interact with IscU prefer to bind one conformational state or the other. From analyses of the NMR spectroscopy-derived network of interactions of ISC proteins, small-angle X-ray scattering (SAXS) data, chemical crosslinking experiments, and functional assays, we have constructed working models for Fe-S cluster assembly and delivery. Future work is needed to validate and refine what has been learned about the E. coli system and to extend these findings to the homologous Fe-S cluster biosynthetic machinery of yeast and human mitochondria. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- Jin Hae Kim
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jameson R Bothe
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - T Reid Alderson
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - John L Markley
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA.
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21
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Vestergaard B, Sayers Z. Investigating increasingly complex macromolecular systems with small-angle X-ray scattering. IUCRJ 2014; 1:523-9. [PMID: 25485132 PMCID: PMC4224470 DOI: 10.1107/s2052252514020843] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 09/17/2014] [Indexed: 05/04/2023]
Abstract
The biological solution small-angle X-ray scattering (BioSAXS) field has undergone tremendous development over recent decades. This means that increasingly complex biological questions can be addressed by the method. An intricate synergy between advances in hardware and software development, data collection and evaluation strategies and implementations that readily allow integration with complementary techniques result in significant results and a rapidly growing user community with ever increasing ambitions. Here, a review of these developments, by including a selection of novel BioSAXS method-ologies and recent results, is given.
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Affiliation(s)
- Bente Vestergaard
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, Copenhagen, DK-2100, Denmark
- Correspondence e-mail:
| | - Zehra Sayers
- Faculty of Engineering and Natural Science, Sabanci University, Orhanli, Istanbul Tuzla 34956, Turkey
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