51
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Lin YW. Rational Design of Artificial Metalloproteins and Metalloenzymes with Metal Clusters. Molecules 2019; 24:E2743. [PMID: 31362341 PMCID: PMC6696605 DOI: 10.3390/molecules24152743] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 01/22/2023] Open
Abstract
Metalloproteins and metalloenzymes play important roles in biological systems by using the limited metal ions, complexes, and clusters that are associated with the protein matrix. The design of artificial metalloproteins and metalloenzymes not only reveals the structure and function relationship of natural proteins, but also enables the synthesis of artificial proteins and enzymes with improved properties and functions. Acknowledging the progress in rational design from single to multiple active sites, this review focuses on recent achievements in the design of artificial metalloproteins and metalloenzymes with metal clusters, including zinc clusters, cadmium clusters, iron-sulfur clusters, and copper-sulfur clusters, as well as noble metal clusters and others. These metal clusters were designed in both native and de novo protein scaffolds for structural roles, electron transfer, or catalysis. Some synthetic metal clusters as functional models of native enzymes are also discussed. These achievements provide valuable insights for deep understanding of the natural proteins and enzymes, and practical clues for the further design of artificial enzymes with functions comparable or even beyond those of natural counterparts.
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Affiliation(s)
- Ying-Wu Lin
- School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China.
- Laboratory of Protein Structure and Function, University of South China, Hengyang 421001, China.
- Hunan Key Laboratory for the Design and Application of Actinide Complexes, University of South China, Hengyang 421001, China.
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52
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Witt A, Pozzi R, Diesch S, Hädicke O, Grammel H. New light on ancient enzymes –
in vitro
CO
2
Fixation by Pyruvate Synthase of
Desulfovibrio africanus
and
Sulfolobus acidocaldarius. FEBS J 2019; 286:4494-4508. [DOI: 10.1111/febs.14981] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 05/13/2019] [Accepted: 07/02/2019] [Indexed: 01/09/2023]
Affiliation(s)
- Andreas Witt
- Hochschule Biberach University of Applied Science Biberach Germany
| | - Roberta Pozzi
- Hochschule Biberach University of Applied Science Biberach Germany
| | - Stephan Diesch
- Hochschule Biberach University of Applied Science Biberach Germany
| | - Oliver Hädicke
- Max Planck Institute for Dynamics of Complex Technical Systems Magdeburg Germany
| | - Hartmut Grammel
- Hochschule Biberach University of Applied Science Biberach Germany
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53
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Bai Y, Chen T, Happe T, Lu Y, Sawyer A. Iron-sulphur cluster biogenesis via the SUF pathway. Metallomics 2019; 10:1038-1052. [PMID: 30019043 DOI: 10.1039/c8mt00150b] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Iron-sulphur (Fe-S) clusters are versatile cofactors, which are essential for key metabolic processes in cells, such as respiration and photosynthesis, and which may have also played a crucial role in establishing life on Earth. They can be found in almost all living organisms, from unicellular prokaryotes and archaea to multicellular animals and plants, and exist in diverse forms. This review focuses on the most ancient Fe-S cluster assembly system, the sulphur utilization factor (SUF) mechanism, which is crucial in bacteria for cell survival under stress conditions such as oxidation and iron starvation, and which is also present in the chloroplasts of green microalgae and plants, where it is responsible for plastidial Fe-S protein maturation. We explain the SUF Fe-S cluster assembly process, the proteins involved, their regulation and provide evolutionary insights. We specifically focus on examples from Fe-S cluster synthesis in the model organisms Escherichia coli and Arabidopsis thaliana and discuss in an in vivo context the assembly of the [FeFe]-hydrogenase H-cluster from Chlamydomonas reinhardtii.
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Affiliation(s)
- Y Bai
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
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54
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Blahut M, Wise CE, Bruno MR, Dong G, Makris TM, Frantom PA, Dunkle JA, Outten FW. Direct observation of intermediates in the SufS cysteine desulfurase reaction reveals functional roles of conserved active-site residues. J Biol Chem 2019; 294:12444-12458. [PMID: 31248989 DOI: 10.1074/jbc.ra119.009471] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/16/2019] [Indexed: 12/25/2022] Open
Abstract
Iron-sulfur (Fe-S) clusters are necessary for the proper functioning of numerous metalloproteins. Fe-S cluster (Isc) and sulfur utilization factor (Suf) pathways are the key biosynthetic routes responsible for generating these Fe-S cluster prosthetic groups in Escherichia coli Although Isc dominates under normal conditions, Suf takes over during periods of iron depletion and oxidative stress. Sulfur acquisition via these systems relies on the ability to remove sulfur from free cysteine using a cysteine desulfurase mechanism. In the Suf pathway, the dimeric SufS protein uses the cofactor pyridoxal 5'-phosphate (PLP) to abstract sulfur from free cysteine, resulting in the production of alanine and persulfide. Despite much progress, the stepwise mechanism by which this PLP-dependent enzyme operates remains unclear. Here, using rapid-mixing kinetics in conjunction with X-ray crystallography, we analyzed the pre-steady-state kinetics of this process while assigning early intermediates of the mechanism. We employed H123A and C364A SufS variants to trap Cys-aldimine and Cys-ketimine intermediates of the cysteine desulfurase reaction, enabling direct observations of these intermediates and associated conformational changes of the SufS active site. Of note, we propose that Cys-364 is essential for positioning the Cys-aldimine for Cα deprotonation, His-123 acts to protonate the Ala-enamine intermediate, and Arg-56 facilitates catalysis by hydrogen bonding with the sulfhydryl of Cys-aldimine. Our results, along with previous SufS structural findings, suggest a detailed model of the SufS-catalyzed reaction from Cys binding to C-S bond cleavage and indicate that Arg-56, His-123, and Cys-364 are critical SufS residues in this C-S bond cleavage pathway.
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Affiliation(s)
- Matthew Blahut
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Courtney E Wise
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Michael R Bruno
- Department of Chemistry and Biochemistry, University of Alabama, Tuscaloosa, Alabama 35487
| | - Guangchao Dong
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Thomas M Makris
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Patrick A Frantom
- Department of Chemistry and Biochemistry, University of Alabama, Tuscaloosa, Alabama 35487
| | - Jack A Dunkle
- Department of Chemistry and Biochemistry, University of Alabama, Tuscaloosa, Alabama 35487.
| | - F Wayne Outten
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208.
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55
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A small RNA controls bacterial sensitivity to gentamicin during iron starvation. PLoS Genet 2019; 15:e1008078. [PMID: 31009454 PMCID: PMC6497325 DOI: 10.1371/journal.pgen.1008078] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 05/02/2019] [Accepted: 03/10/2019] [Indexed: 02/06/2023] Open
Abstract
Phenotypic resistance describes a bacterial population that becomes transiently resistant to an antibiotic without requiring a genetic change. We here investigated the role of the small regulatory RNA (sRNA) RyhB, a key contributor to iron homeostasis, in the phenotypic resistance of Escherichia coli to various classes of antibiotics. We found that RyhB induces phenotypic resistance to gentamicin, an aminoglycoside that targets the ribosome, when iron is scarce. RyhB induced resistance is due to the inhibition of respiratory complexes Nuo and Sdh activities. These complexes, which contain numerous Fe-S clusters, are crucial for generating a proton motive force (pmf) that allows gentamicin uptake. RyhB regulates negatively the expression of nuo and sdh, presumably by binding to their mRNAs and, as a consequence, inhibiting their translation. We further show that Isc Fe-S biogenesis machinery is essential for the maturation of Nuo. As RyhB also limits levels of the Isc machinery, we propose that RyhB may also indirectly impact the maturation of Nuo and Sdh. Notably, our study shows that respiratory complexes activity levels are predictive of the bacterial sensitivity to gentamicin. Altogether, these results unveil a new role for RyhB in the adaptation to antibiotic stress, an unprecedented consequence of its role in iron starvation stress response. Understanding the mechanisms at work behind bacterial antibiotic resistance has become a major health issue in the face of the antibiotics crisis. Here, we show that RyhB, a bacterial small regulatory RNA, decreases the sensitivity of Escherichia coli to the antibiotic gentamicin when iron is scarce, an environmental situation prevalent during host-pathogen interactions. This phenotypic resistance is related to the activity of the respiratory complexes Nuo and Sdh, which are producing the proton motive force allowing antibiotic uptake. Altogether, this study points out to a major role for RyhB in escaping antibacterial action.
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56
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Goodpaster JD. Theoretical Chemistry Answers Bimolecular Signaling Debate in [4Fe4S] Proteins. Chem 2019. [DOI: 10.1016/j.chempr.2018.12.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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57
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Khodour Y, Kaguni LS, Stiban J. Iron-sulfur clusters in nucleic acid metabolism: Varying roles of ancient cofactors. Enzymes 2019; 45:225-256. [PMID: 31627878 DOI: 10.1016/bs.enz.2019.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Despite their relative simplicity, iron-sulfur clusters have been omnipresent as cofactors in myriad cellular processes such as oxidative phosphorylation and other respiratory pathways. Recent research advances confirm the presence of different clusters in enzymes involved in nucleic acid metabolism. Iron-sulfur clusters can therefore be considered hallmarks of cellular metabolism. Helicases, nucleases, glycosylases, DNA polymerases and transcription factors, among others, incorporate various types of clusters that serve differing roles. In this chapter, we review our current understanding of the identity and functions of iron-sulfur clusters in DNA and RNA metabolizing enzymes, highlighting their importance as regulators of cellular function.
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Affiliation(s)
- Yara Khodour
- Department of Biology and Biochemistry, Birzeit University, West Bank, Palestine
| | - Laurie S Kaguni
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
| | - Johnny Stiban
- Department of Biology and Biochemistry, Birzeit University, West Bank, Palestine.
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58
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Wijerathne H, Yao H, Wang Y, Lovell S, Battaile KP, Rivera M. Bfd, a New Class of [2Fe-2S] Protein That Functions in Bacterial Iron Homeostasis, Requires a Structural Anion Binding Site. Biochemistry 2018; 57:5533-5543. [PMID: 30183257 DOI: 10.1021/acs.biochem.8b00823] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mobilization of iron from bacterioferritin (BfrB) requires specific interactions with a [2Fe-2S] ferredoxin (Bfd). Blocking the BfrB:Bfd interaction results in irreversible iron accumulation in BfrB and iron deficiency in the cytosol [Eshelman, K., et al. (2017) Metallomics 9, 646-659]. The only known Bfd structure, which was obtained in complex with BfrB (Protein Data Bank entry 4E6K ), indicated a new fold and suggested that the stability of Bfd is aided by an anion binding site consisting of R26, R29, and K46. We investigated the Bfd fold using site-directed mutagenesis, X-ray crystallography, and biochemistry in solution. The X-ray structure, which is nearly identical to that of Bfd in the BfrB:Bfd complex, shows that the [2Fe-2S] cluster preorganizes residues at the BfrB:Bfd interface into a structure complementary to the Bfd binding site on BfrB. Studies in solution showed rapid loss of the [2Fe-2S] cluster at a low ionic strength but higher stability with an increasing ionic strength, thus supporting a structural anion binding site. Structures of the R26E and R26E/K46Y mutants are nearly identical to that of Bfd, except for a new network of hydrogen bonds stabilizing the region encompassing the former anion binding site. The stability of the R26E and R26E/K46Y mutants, which is weakly and completely independent of solution ionic strength, respectively, corroborates that Bfd requires an anion binding site. The mutations, which caused only small changes to the strength of the BfrB:Bfd interaction and mobilization of iron from BfrB, indicate that the anion binding site in Bfd serves primarily a structural role.
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Affiliation(s)
- Harshani Wijerathne
- Department of Chemistry , University of Kansas , Multidisciplinary Research Building, 2030 Becker Drive , Lawrence , Kansas 66047 , United States
| | - Huili Yao
- Department of Chemistry , Louisiana State University , 229A Choppin Hall , Baton Rouge , Louisiana 70803 , United States
| | - Yan Wang
- Department of Chemistry , University of Kansas , Multidisciplinary Research Building, 2030 Becker Drive , Lawrence , Kansas 66047 , United States
| | - Scott Lovell
- Protein Structure Laboratory, Del Shankel Structural Biology Center , University of Kansas , 2034 Becker Drive , Lawrence , Kansas 66047 , United States
| | - Kevin P Battaile
- IMCA-CAT , Hauptman Woodward Medical Research Institute , 9700 South Cass Avenue, Building 435A , Argonne , Illinois 60439 , United States
| | - Mario Rivera
- Department of Chemistry , Louisiana State University , 229A Choppin Hall , Baton Rouge , Louisiana 70803 , United States
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59
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Cai K, Frederick RO, Dashti H, Markley JL. Architectural Features of Human Mitochondrial Cysteine Desulfurase Complexes from Crosslinking Mass Spectrometry and Small-Angle X-Ray Scattering. Structure 2018; 26:1127-1136.e4. [PMID: 29983374 PMCID: PMC6082693 DOI: 10.1016/j.str.2018.05.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/16/2018] [Accepted: 05/24/2018] [Indexed: 11/19/2022]
Abstract
Cysteine desulfurase plays a central role in mitochondrial iron-sulfur cluster biogenesis by generating sulfur through the conversion of L-cysteine to L-alanine and by serving as the platform for assembling other components of the biosynthetic machinery, including ISCU, frataxin, and ferredoxin. The human mitochondrial cysteine desulfurase complex consists of two copies each of NFS1, ISD11, and acyl carrier protein. We describe results from chemical crosslinking coupled with tandem mass spectrometry and small-angle X-ray scattering studies that are consistent with a closed NFS1 dimer rather than an open one for both the cysteine desulfurase-ISCU and cysteine desulfurase-ISCU-frataxin complexes. We present a structural model for the cysteine desulfurase-ISCU-frataxin complex derived from chemical crosslinking restraints in conjunction with the recent crystal structure of the cysteine desulfurase-ISCU-zinc complex and distance constraints from nuclear magnetic resonance.
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Affiliation(s)
- Kai Cai
- Biochemistry Department, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA
| | - Ronnie O Frederick
- Biochemistry Department, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA
| | - Hesam Dashti
- Biochemistry Department, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA
| | - John L Markley
- Biochemistry Department, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA.
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60
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Gurgel-Giannetti J, Lynch DS, de Paiva ARB, Lucato LT, Yamamoto G, Thomsen C, Basu S, Freua F, Giannetti AV, de Assis BDR, Ribeiro MDO, Barcelos I, Sayão Souza K, Monti F, Melo US, Amorim S, Silva LGL, Macedo-Souza LI, Vianna-Morgante AM, Hirano M, Van der Knaap MS, Lill R, Vainzof M, Oldfors A, Houlden H, Kok F. A novel complex neurological phenotype due to a homozygous mutation in FDX2. Brain 2018; 141:2289-2298. [PMID: 30010796 PMCID: PMC6061701 DOI: 10.1093/brain/awy172] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 03/30/2018] [Accepted: 04/26/2018] [Indexed: 11/14/2022] Open
Abstract
Defects in iron-sulphur [Fe-S] cluster biogenesis are increasingly recognized as causing neurological disease. Mutations in a number of genes that encode proteins involved in mitochondrial [Fe-S] protein assembly lead to complex neurological phenotypes. One class of proteins essential in the early cluster assembly are ferredoxins. FDX2 is ubiquitously expressed and is essential in the de novo formation of [2Fe-2S] clusters in humans. We describe and genetically define a novel complex neurological syndrome identified in two Brazilian families, with a novel homozygous mutation in FDX2. Patients were clinically evaluated, underwent MRI, nerve conduction studies, EMG and muscle biopsy. To define the genetic aetiology, a combination of homozygosity mapping and whole exome sequencing was performed. We identified six patients from two apparently unrelated families with autosomal recessive inheritance of a complex neurological phenotype involving optic atrophy and nystagmus developing by age 3, followed by myopathy and recurrent episodes of cramps, myalgia and muscle weakness in the first or second decade of life. Sensory-motor axonal neuropathy led to progressive distal weakness. MRI disclosed a reversible or partially reversible leukoencephalopathy. Muscle biopsy demonstrated an unusual pattern of regional succinate dehydrogenase and cytochrome c oxidase deficiency with iron accumulation. The phenotype was mapped in both families to the same homozygous missense mutation in FDX2 (c.431C > T, p.P144L). The deleterious effect of the mutation was validated by real-time reverse transcription polymerase chain reaction and western blot analysis, which demonstrated normal expression of FDX2 mRNA but severely reduced expression of FDX2 protein in muscle tissue. This study describes a novel complex neurological phenotype with unusual MRI and muscle biopsy features, conclusively mapped to a mutation in FDX2, which encodes a ubiquitously expressed mitochondrial ferredoxin essential for early [Fe-S] cluster biogenesis.
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Affiliation(s)
| | - David S Lynch
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
- Leonard Wolfson Experimental Neurology Centre, UCL Institute of Neurology, London, UK
| | | | - Leandro Tavares Lucato
- Neuroradiology Section, Hospital das Clínicas da Universidade de São Paulo, São Paulo, Brazil
| | - Guilherme Yamamoto
- Human Genome and Stem Cell Research Center, Department of Genetics and Evolutionary Biology, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Christer Thomsen
- Department of Pathology and Genetics, Sahlgrenska University Hospital, University of Gothenburg, Sweden
| | - Somsuvro Basu
- Institute for Cytobiology and Cytopathology, Philipps-Universität Marburg, Robert-Koch-Strasse 6, 35032 Marburg, Germany
| | - Fernando Freua
- Neurogenetics Unit, Neurology Department, Hospital das Clínicas da Universidade de São Paulo, São Paulo, Brazil
| | | | - Bruno Della Ripa de Assis
- Neurogenetics Unit, Neurology Department, Hospital das Clínicas da Universidade de São Paulo, São Paulo, Brazil
| | - Mara Dell Ospedale Ribeiro
- Neurogenetics Unit, Neurology Department, Hospital das Clínicas da Universidade de São Paulo, São Paulo, Brazil
| | - Isabella Barcelos
- Neurogenetics Unit, Neurology Department, Hospital das Clínicas da Universidade de São Paulo, São Paulo, Brazil
| | - Katiane Sayão Souza
- Neurogenetics Unit, Neurology Department, Hospital das Clínicas da Universidade de São Paulo, São Paulo, Brazil
| | - Fernanda Monti
- Neurogenetics Unit, Neurology Department, Hospital das Clínicas da Universidade de São Paulo, São Paulo, Brazil
| | - Uirá Souto Melo
- Human Genome and Stem Cell Research Center, Department of Genetics and Evolutionary Biology, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Simone Amorim
- Neurogenetics Unit, Neurology Department, Hospital das Clínicas da Universidade de São Paulo, São Paulo, Brazil
| | - Leonardo G L Silva
- Human Genome and Stem Cell Research Center, Department of Genetics and Evolutionary Biology, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Lúcia Inês Macedo-Souza
- Human Genome and Stem Cell Research Center, Department of Genetics and Evolutionary Biology, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Angela M Vianna-Morgante
- Human Genome and Stem Cell Research Center, Department of Genetics and Evolutionary Biology, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Michio Hirano
- Department of Neurology, Columbia University Medical Center, New York, USA
| | - Marjo S Van der Knaap
- Department of Child Neurology, VU University Medical Center, Amsterdam, The Netherlands
| | - Roland Lill
- Institute for Cytobiology and Cytopathology, Philipps-Universität Marburg, Robert-Koch-Strasse 6, 35032 Marburg, Germany
- LOEWE Center for Synthetic Microbiology, SynMikro, Hans-Meerwein-Strasse, 35043 Marburg, Germany
| | - Mariz Vainzof
- Human Genome and Stem Cell Research Center, Department of Genetics and Evolutionary Biology, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Anders Oldfors
- Department of Pathology and Genetics, Sahlgrenska University Hospital, University of Gothenburg, Sweden
| | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
- Leonard Wolfson Experimental Neurology Centre, UCL Institute of Neurology, London, UK
| | - Fernando Kok
- Neurogenetics Unit, Neurology Department, Hospital das Clínicas da Universidade de São Paulo, São Paulo, Brazil
- Human Genome and Stem Cell Research Center, Department of Genetics and Evolutionary Biology, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
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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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Lee SH, Choi DS, Kuk SK, Park CB. Photobiokatalyse: Aktivierung von Redoxenzymen durch direkten oder indirekten Transfer photoinduzierter Elektronen. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201710070] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sahng Ha Lee
- Department of Materials Science and EngineeringKorea Advanced Institute of Science and Technology (KAIST) 335 Science Road Daejeon 305-701 Republik Korea
| | - Da Som Choi
- Department of Materials Science and EngineeringKorea Advanced Institute of Science and Technology (KAIST) 335 Science Road Daejeon 305-701 Republik Korea
| | - Su Keun Kuk
- Department of Materials Science and EngineeringKorea Advanced Institute of Science and Technology (KAIST) 335 Science Road Daejeon 305-701 Republik Korea
| | - Chan Beum Park
- Department of Materials Science and EngineeringKorea Advanced Institute of Science and Technology (KAIST) 335 Science Road Daejeon 305-701 Republik Korea
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63
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Inorganic iron-sulfur clusters enhance electron transport when used for wiring the NAD-glucose dehydrogenase based redox system. Mikrochim Acta 2018; 185:337. [PMID: 29946767 PMCID: PMC6019433 DOI: 10.1007/s00604-018-2871-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 06/08/2018] [Indexed: 11/06/2022]
Abstract
Wiring the active site of an enzyme directly to an electrode is the key to ensuring efficient electron transfer for the proper performance of enzyme-based bioelectronic systems. Iron-sulfur complexes, the first link between proteins and mediating molecules in the biological electron transport chain(s), possess an intrinsic electron transport capability. The authors demonstrate the application of inorganic iron-sulfur clusters (Fe-S) viz. FeS, FeS2, Fe2S3, and Fe3S4, as molecular wires to mediate electron transport between a glucose-selective redox enzyme and the gold electrode. It is shown that Fe-S can emulate the functionality of the natural electron transport chain. Voltammetric studies indicate a significant improvement in electron transport, surface coverage, and resilience achieved by the Fe-S-based glucose anodes when compared to a conventional pyrroloquinoline quinone (PQQ)-based electrode. The Fe-S-based glucose anodes showed glucose oxidation at a potential of +0.5 V vs. Ag/AgCl with Tris-HCl buffer (pH 8) acting as a carrier. The current densities positively correlated with the concentrations of glucose in the range 0.1–100 mM displaying detection limits of 0.77 mM (FeS), 1.22 mM (FeS2), 2.95 mM (Fe2S3), and 14.57 mM (Fe3S4). The metal-anchorable sulfur atom, the strong π-coordinating iron atom, the favorable redox properties, low cost, and natural abundance make Fe-S an excellent electron-mediating relay capable of wiring redox active sites to electrode surfaces. Schematic representation of inorganic iron-sulfur clusters used as molecular wires to facilitate direct electron transfer between NAD-glucose dehydrogenase and the gold electrode. The iron-sulfur based glucose anodes improve current response to selectively sense glucose concentrations in the range 0.1–100 mM. ![]()
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Cai K, Frederick RO, Tonelli M, Markley JL. Interactions of iron-bound frataxin with ISCU and ferredoxin on the cysteine desulfurase complex leading to Fe-S cluster assembly. J Inorg Biochem 2018; 183:107-116. [PMID: 29576242 PMCID: PMC5951399 DOI: 10.1016/j.jinorgbio.2018.03.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/08/2018] [Accepted: 03/12/2018] [Indexed: 12/15/2022]
Abstract
Frataxin (FXN) is involved in mitochondrial iron‑sulfur (Fe-S) cluster biogenesis and serves to accelerate Fe-S cluster formation. FXN deficiency is associated with Friedreich ataxia, a neurodegenerative disease. We have used a combination of isothermal titration calorimetry and multinuclear NMR spectroscopy to investigate interactions among the components of the biological machine that carries out the assembly of iron‑sulfur clusters in human mitochondria. Our results show that FXN tightly binds a single Fe2+ but not Fe3+. While FXN (with or without bound Fe2+) does not bind the scaffold protein ISCU directly, the two proteins interact mutually when each is bound to the cysteine desulfurase complex ([NFS1]2:[ISD11]2:[Acp]2), abbreviated as (NIA)2, where "N" represents the cysteine desulfurase (NFS1), "I" represents the accessory protein (ISD11), and "A" represents acyl carrier protein (Acp). FXN binds (NIA)2 weakly in the absence of ISCU but more strongly in its presence. Fe2+-FXN binds to the (NIA)2-ISCU2 complex without release of iron. However, upon the addition of both l-cysteine and a reductant (either reduced FDX2 or DTT), Fe2+ is released from FXN as consistent with Fe2+-FXN being the proximal source of iron for Fe-S cluster assembly.
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Affiliation(s)
- Kai Cai
- National Magnetic Resonance Facility at Madison and Biochemistry Department, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, United States
| | - Ronnie O Frederick
- National Magnetic Resonance Facility at Madison and Biochemistry Department, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, United States
| | - Marco Tonelli
- National Magnetic Resonance Facility at Madison and Biochemistry Department, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, United States
| | - John L Markley
- National Magnetic Resonance Facility at Madison and Biochemistry Department, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, United States.
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65
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Lee SH, Choi DS, Kuk SK, Park CB. Photobiocatalysis: Activating Redox Enzymes by Direct or Indirect Transfer of Photoinduced Electrons. Angew Chem Int Ed Engl 2018; 57:7958-7985. [PMID: 29194901 DOI: 10.1002/anie.201710070] [Citation(s) in RCA: 190] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/21/2017] [Indexed: 01/01/2023]
Abstract
Biocatalytic transformation has received increasing attention in the green synthesis of chemicals because of the diversity of enzymes, their high catalytic activities and specificities, and mild reaction conditions. The idea of solar energy utilization in chemical synthesis through the combination of photocatalysis and biocatalysis provides an opportunity to make the "green" process greener. Oxidoreductases catalyze redox transformation of substrates by exchanging electrons at the enzyme's active site, often with the aid of electron mediator(s) as a counterpart. Recent progress indicates that photoinduced electron transfer using organic (or inorganic) photosensitizers can activate a wide spectrum of redox enzymes to catalyze fuel-forming reactions (e.g., H2 evolution, CO2 reduction) and synthetically useful reductions (e.g., asymmetric reduction, oxygenation, hydroxylation, epoxidation, Baeyer-Villiger oxidation). This Review provides an overview of recent advances in light-driven activation of redox enzymes through direct or indirect transfer of photoinduced electrons.
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Affiliation(s)
- Sahng Ha Lee
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 335 Science Road, Daejeon, 305-701, Republic of Korea
| | - Da Som Choi
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 335 Science Road, Daejeon, 305-701, Republic of Korea
| | - Su Keun Kuk
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 335 Science Road, Daejeon, 305-701, Republic of Korea
| | - Chan Beum Park
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 335 Science Road, Daejeon, 305-701, Republic of Korea
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66
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Cardenas-Rodriguez M, Chatzi A, Tokatlidis K. Iron-sulfur clusters: from metals through mitochondria biogenesis to disease. J Biol Inorg Chem 2018; 23:509-520. [PMID: 29511832 PMCID: PMC6006200 DOI: 10.1007/s00775-018-1548-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 02/22/2018] [Indexed: 01/12/2023]
Abstract
Iron–sulfur clusters are ubiquitous inorganic co-factors that contribute to a wide range of cell pathways including the maintenance of DNA integrity, regulation of gene expression and protein translation, energy production, and antiviral response. Specifically, the iron–sulfur cluster biogenesis pathways include several proteins dedicated to the maturation of apoproteins in different cell compartments. Given the complexity of the biogenesis process itself, the iron–sulfur research area constitutes a very challenging and interesting field with still many unaddressed questions. Mutations or malfunctions affecting the iron–sulfur biogenesis machinery have been linked with an increasing amount of disorders such as Friedreich’s ataxia and various cardiomyopathies. This review aims to recap the recent discoveries both in the yeast and human iron–sulfur cluster arena, covering recent discoveries from chemistry to disease.
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Affiliation(s)
- Mauricio Cardenas-Rodriguez
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Afroditi Chatzi
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Kostas Tokatlidis
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
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67
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Cai K, Frederick RO, Tonelli M, Markley JL. ISCU(M108I) and ISCU(D39V) Differ from Wild-Type ISCU in Their Failure To Form Cysteine Desulfurase Complexes Containing Both Frataxin and Ferredoxin. Biochemistry 2018; 57:1491-1500. [PMID: 29406711 PMCID: PMC5842376 DOI: 10.1021/acs.biochem.7b01234] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 02/06/2018] [Indexed: 01/09/2023]
Abstract
Whereas iron-sulfur (Fe-S) cluster assembly on the wild-type scaffold protein ISCU, as catalyzed by the human cysteine desulfurase complex (NIA)2, exhibits a requirement for frataxin (FXN), in yeast, ISCU variant M108I has been shown to bypass the FXN requirement. Wild-type ISCU populates two interconverting conformational states: one structured and one dynamically disordered. We show here that variants ISCU(M108I) and ISCU(D39V) of human ISCU populate only the structured state. We have compared the properties of ISCU, ISCU(M108I), and ISCU(D39V), with and without FXN, in both the cysteine desulfurase step of Fe-S cluster assembly and the overall Fe-S cluster assembly reaction catalyzed by (NIA)2. In the cysteine desulfurase step with dithiothreitol (DTT) as the reductant, FXN was found to stimulate cysteine desulfurase activity with both the wild-type and structured variants, although the effect was less prominent with ISCU(D39V) than with the wild-type or ISCU(M108I). In overall Fe-S cluster assembly, frataxin was found to stimulate cluster assembly with both the wild-type and structured variants when the reductant was DTT; however, with the physiological reductant, reduced ferredoxin 2 (rdFDX2), FXN stimulated the reaction with wild-type ISCU but not with either ISCU(M108I) or ISCU(D39V). Nuclear magnetic resonance titration experiments revealed that wild-type ISCU, FXN, and rdFDX2 all bind to (NIA)2. However, when ISCU was replaced by the fully structured variant ISCU(M108I), the addition of rdFDX2 to the [NIA-ISCU(M108I)-FXN]2 complex led to the release of FXN. Thus, the displacement of FXN by rdFDX2 explains the failure of FXN to stimulate Fe-S cluster assembly on ISCU(M108I).
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Affiliation(s)
- Kai Cai
- National Magnetic Resonance
Facility at Madison and Department of Biochemistry, University of Wisconsin—Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - Ronnie O. Frederick
- National Magnetic Resonance
Facility at Madison and Department of Biochemistry, University of Wisconsin—Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - Marco Tonelli
- National Magnetic Resonance
Facility at Madison and Department of Biochemistry, University of Wisconsin—Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - John L. Markley
- National Magnetic Resonance
Facility at Madison and Department of Biochemistry, University of Wisconsin—Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
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68
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Taguchi AT, Miyajima-Nakano Y, Fukazawa R, Lin MT, Baldansuren A, Gennis RB, Hasegawa K, Kumasaka T, Dikanov SA, Iwasaki T. Unpaired Electron Spin Density Distribution across Reduced [2Fe-2S] Cluster Ligands by 13Cβ-Cysteine Labeling. Inorg Chem 2017; 57:741-746. [DOI: 10.1021/acs.inorgchem.7b02676] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alexander T. Taguchi
- Department of Biochemistry and Molecular Biology, Nippon Medical School, Sendagi, Tokyo 113-8602, Japan
| | - Yoshiharu Miyajima-Nakano
- Department of Biochemistry and Molecular Biology, Nippon Medical School, Sendagi, Tokyo 113-8602, Japan
| | - Risako Fukazawa
- Department of Biochemistry and Molecular Biology, Nippon Medical School, Sendagi, Tokyo 113-8602, Japan
| | | | - Amgalanbaatar Baldansuren
- Department of Veterinary
Clinical Medicine, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Robert B. Gennis
- Department of Biochemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Kazuya Hasegawa
- Japan Synchrotron Radiation Research Institute (SPring-8/JASRI), Sayo, Hyogo 679-5198, Japan
| | - Takashi Kumasaka
- Japan Synchrotron Radiation Research Institute (SPring-8/JASRI), Sayo, Hyogo 679-5198, Japan
| | - Sergei A. Dikanov
- Department of Veterinary
Clinical Medicine, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Toshio Iwasaki
- Department of Biochemistry and Molecular Biology, Nippon Medical School, Sendagi, Tokyo 113-8602, Japan
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69
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Pérard J, Ollagnier de Choudens S. Iron-sulfur clusters biogenesis by the SUF machinery: close to the molecular mechanism understanding. J Biol Inorg Chem 2017; 23:581-596. [PMID: 29280002 PMCID: PMC6006206 DOI: 10.1007/s00775-017-1527-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 12/11/2017] [Indexed: 11/30/2022]
Abstract
Iron–sulfur clusters (Fe–S) are amongst the most ancient and versatile inorganic cofactors in nature which are used by proteins for fundamental biological processes. Multiprotein machineries (NIF, ISC, SUF) exist for Fe–S cluster biogenesis which are mainly conserved from bacteria to human. SUF system (sufABCDSE operon) plays a general role in many bacteria under conditions of iron limitation or oxidative stress. In this mini-review, we will summarize the current understanding of the molecular mechanism of Fe–S biogenesis by SUF. The advances in our understanding of the molecular aspects of SUF originate from biochemical, biophysical and recent structural studies. Combined with recent in vivo experiments, the understanding of the Fe–S biogenesis mechanism considerably moved forward.
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Affiliation(s)
- J Pérard
- Laboratoire de Chimie et Biologie des Métaux, Biocat, Université Grenoble Alpes, Grenoble, France.,Laboratoire de Chimie et Biologie des Métaux, CNRS, BioCat, UMR 5249, Grenoble, France.,CEA-Grenoble, DRF/BIG/CBM, Grenoble, France
| | - Sandrine Ollagnier de Choudens
- Laboratoire de Chimie et Biologie des Métaux, Biocat, Université Grenoble Alpes, Grenoble, France. .,Laboratoire de Chimie et Biologie des Métaux, CNRS, BioCat, UMR 5249, Grenoble, France. .,CEA-Grenoble, DRF/BIG/CBM, Grenoble, France.
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70
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Möller F, Piontek S, Miller RG, Apfel UP. From Enzymes to Functional Materials-Towards Activation of Small Molecules. Chemistry 2017; 24:1471-1493. [PMID: 28816379 DOI: 10.1002/chem.201703451] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 08/15/2017] [Indexed: 12/12/2022]
Abstract
The design of non-noble metal-containing heterogeneous catalysts for the activation of small molecules is of utmost importance for our society. While nature possesses very sophisticated machineries to perform such conversions, rationally designed catalytic materials are rare. Herein, we aim to raise the awareness of the overall common design and working principles of catalysts incorporating aspects of biology, chemistry, and material sciences.
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Affiliation(s)
- Frauke Möller
- Inorganic Chemistry I/ Bioinorganic Chemistry, Ruhr-University Bochum, Universitätsstaße 150, 44801, Bochum, Germany
| | - Stefan Piontek
- Inorganic Chemistry I/ Bioinorganic Chemistry, Ruhr-University Bochum, Universitätsstaße 150, 44801, Bochum, Germany
| | - Reece G Miller
- Inorganic Chemistry I/ Bioinorganic Chemistry, Ruhr-University Bochum, Universitätsstaße 150, 44801, Bochum, Germany
| | - Ulf-Peter Apfel
- Inorganic Chemistry I/ Bioinorganic Chemistry, Ruhr-University Bochum, Universitätsstaße 150, 44801, Bochum, Germany
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71
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Improved analytical techniques of sulfur isotopic composition in nanomole quantities by MC-ICP-MS. Anal Chim Acta 2017; 988:34-40. [PMID: 28916101 DOI: 10.1016/j.aca.2017.08.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 08/02/2017] [Accepted: 08/07/2017] [Indexed: 11/20/2022]
Abstract
We propose an improved method for precise sulfur isotopic measurements by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) in conjunction with a membrane desolvation nebulization system. The problems of sulfur loss through the membrane desolvation apparatus are carefully quantified and resolved. The method overcomes low intrinsic sulfur transmission through the instrument, which was initially 1% when operating at a desolvation temperature of 160 °C. Sulfur loss through the membrane desolvation apparatus was resolved by doping with sodium. A Na/S ratio of 2 mol mol-1 produced sulfur transmissions with 98% recovery. Samples of 3 nmol (100 ng) sulfur achieved an external precision of ±0.18‰ (2 SD) for δ34S and ±0.10‰ (2 SD) for Δ33S (uppercase delta expresses the extent of mass-independent isotopic fractionation). Measurements made on certified reference materials and in-house standards demonstrate analytical accuracy and reproducibility. We applied the method to examine microbial-induced sulfur transformation in marine sediment pore waters from the sulfate-methane transition zone. The technique is quite versatile, and can be applied to a range of materials, including natural waters and minerals.
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72
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Jaroschinsky M, Pinske C, Gary Sawers R. Differential effects of isc operon mutations on the biosynthesis and activity of key anaerobic metalloenzymes in Escherichia coli. MICROBIOLOGY-SGM 2017. [PMID: 28640740 DOI: 10.1099/mic.0.000481] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Escherichia coli has two machineries for the synthesis of FeS clusters, namely Isc (iron-sulfur cluster) and Suf (sulfur formation). The Isc machinery, encoded by the iscRSUA-hscBA-fdx-iscXoperon, plays a crucial role in the biogenesis of FeS clusters for the oxidoreductases of aerobic metabolism. Less is known, however, about the role of ISC in the maturation of key multi-subunit metalloenzymes of anaerobic metabolism. Here, we determined the contribution of each iscoperon gene product towards the functionality of the major anaerobic oxidoreductases in E. coli, including three [NiFe]-hydrogenases (Hyd), two respiratory formate dehydrogenases (FDH) and nitrate reductase (NAR). Mutants lacking the cysteine desulfurase, IscS, lacked activity of all six enzymes, as well as the activity of fumaratereductase, and this was due to deficiencies in enzyme biosynthesis, maturation or FeS cluster insertion into electron-transfer components. Notably, based on anaerobic growth characteristics and metabolite patterns, the activity of the radical-S-adenosylmethionine enzyme pyruvate formate-lyase activase was independent of IscS, suggesting that FeS biogenesis for this ancient enzyme has different requirements. Mutants lacking either the scaffold protein IscU, the ferredoxin Fdx or the chaperones HscA or HscB had similar enzyme phenotypes: five of the oxidoreductases were essentially inactive, with the exception being the Hyd-3 enzyme, which formed part of the H2-producing formate hydrogenlyase (FHL) complex. Neither the frataxin-homologue CyaY nor the IscX protein was essential for synthesis of the three Hyd enzymes. Thus, while IscS is essential for H2 production in E. coli, the other ISC components are non-essential.
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Affiliation(s)
- Monique Jaroschinsky
- Institute for Biology/Microbiology, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Str 3, 06120 Halle (Saale), Germany.,Present address: ICP Analytik GmbH & Co. KG, Brandenburger Platz 1, 24211 Preetz, Germany
| | - Constanze Pinske
- Institute for Biology/Microbiology, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Str 3, 06120 Halle (Saale), Germany
| | - R Gary Sawers
- Institute for Biology/Microbiology, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Str 3, 06120 Halle (Saale), Germany
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73
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Tawfik SA, Weston L, Cui XY, Ringer SP, Stampfl C. Near-Perfect Spin Filtering and Negative Differential Resistance in an Fe(II)S Complex. J Phys Chem Lett 2017; 8:2189-2194. [PMID: 28457138 DOI: 10.1021/acs.jpclett.7b00551] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Density functional theory and nonequilibrium Green's function calculations have been used to explore spin-resolved transport through the high-spin state of an iron(II)sulfur single molecular magnet. Our results show that this molecule exhibits near-perfect spin filtering, where the spin-filtering efficiency is above 99%, as well as significant negative differential resistance centered at a low bias voltage. The rise in the spin-up conductivity up to the bias voltage of 0.4 V is dominated by a conductive lowest unoccupied molecular orbital, and this is accompanied by a slight increase in the magnetic moment of the Fe atom. The subsequent drop in the spin-up conductivity is because the conductive channel moves to the highest occupied molecular orbital, which has a lower conductance contribution. This is accompanied by a drop in the magnetic moment of the Fe atom. These two exceptional properties, and the fact that the onset of negative differential resistance occurs at low bias voltage, suggests the potential of the molecule in nanoelectronic and nanospintronic applications.
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Affiliation(s)
| | - Leigh Weston
- Materials Department, University of California , Santa Barbara, California, United States
| | - X Y Cui
- Australian Centre for Microscopy and Microanalysis, and School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney , New South Wales, 2006, Australia
| | - S P Ringer
- Australian Centre for Microscopy and Microanalysis, and School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney , New South Wales, 2006, Australia
| | - C Stampfl
- School of Physics, The University of Sydney , New South Wales, 2006, Australia
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74
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75
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Bergner M, Roy L, Dechert S, Neese F, Ye S, Meyer F. Ligand Rearrangements at Fe/S Cofactors: Slow Isomerization of a Biomimetic [2Fe-2S] Cluster. Angew Chem Int Ed Engl 2017; 56:4882-4886. [DOI: 10.1002/anie.201612621] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Indexed: 02/01/2023]
Affiliation(s)
- Marie Bergner
- Universität Göttingen; Institut für Anorganische Chemie; Tammannstrasse 4 37077 Göttingen Germany
| | - Lisa Roy
- Max-Planck-Institut für Chemische Energiekonversion; Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
| | - Sebastian Dechert
- Universität Göttingen; Institut für Anorganische Chemie; Tammannstrasse 4 37077 Göttingen Germany
| | - Frank Neese
- Max-Planck-Institut für Chemische Energiekonversion; Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
| | - Shengfa Ye
- Max-Planck-Institut für Chemische Energiekonversion; Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
| | - Franc Meyer
- Universität Göttingen; Institut für Anorganische Chemie; Tammannstrasse 4 37077 Göttingen Germany
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76
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Bergner M, Roy L, Dechert S, Neese F, Ye S, Meyer F. Ligandenumlagerungen an Fe/S-Cofaktoren: langsame Isomerisierung eines biomimetischen [2Fe-2S]-Clusters. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201612621] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Marie Bergner
- Universität Göttingen; Institut für Anorganische Chemie; Tammannstraße 4 37077 Göttingen Deutschland
| | - Lisa Roy
- Max-Planck-Institut für Chemische Energiekonversion; Stiftstraße 34-36 45470 Mülheim an der Ruhr Deutschland
| | - Sebastian Dechert
- Universität Göttingen; Institut für Anorganische Chemie; Tammannstraße 4 37077 Göttingen Deutschland
| | - Frank Neese
- Max-Planck-Institut für Chemische Energiekonversion; Stiftstraße 34-36 45470 Mülheim an der Ruhr Deutschland
| | - Shengfa Ye
- Max-Planck-Institut für Chemische Energiekonversion; Stiftstraße 34-36 45470 Mülheim an der Ruhr Deutschland
| | - Franc Meyer
- Universität Göttingen; Institut für Anorganische Chemie; Tammannstraße 4 37077 Göttingen Deutschland
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77
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Bergner M, Dechert S, Demeshko S, Kupper C, Mayer JM, Meyer F. Model of the MitoNEET [2Fe-2S] Cluster Shows Proton Coupled Electron Transfer. J Am Chem Soc 2017; 139:701-707. [PMID: 28055193 PMCID: PMC5812485 DOI: 10.1021/jacs.6b09180] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
MitoNEET is an outer membrane protein whose exact function remains unclear, though a role of this protein in redox and iron sensing as well as in controlling maximum mitochondrial respiratory rates has been discussed. It was shown to contain a redox active and acid labile [2Fe-2S] cluster which is ligated by one histidine and three cysteine residues. Herein we present the first synthetic analogue with biomimetic {SN/S2} ligation which could be structurally characterized in its diferric form, 52-. In addition to being a high fidelity structural model for the biological cofactor, the complex is shown to mediate proton coupled electron transfer (PCET) at the {SN} ligated site, pointing at a potential functional role of the enzyme's unique His ligand. Full PCET thermodynamic square schemes for the mitoNEET model 52- and a related homoleptic {SN/SN} capped [2Fe-2S] cluster 42- are established, and kinetics of PCET reactivity are investigated by double-mixing stopped-flow experiments for both complexes. While the N-H bond dissociation free energy (BDFE) of 5H2- (230 ± 4 kJ mol-1) and the free energy ΔG°PCET for the reaction with TEMPO (-48.4 kJ mol-1) are very similar to values for the homoleptic cluster 4H2- (232 ± 4 kJ mol-1, -46.3 kJ mol-1) the latter is found to react significantly faster than the mitoNEET model (data for 5H2-: k = 135 ± 27 M-1 s-1, ΔH‡ = 17.6 ± 3.0 kJ mol-1, ΔS‡ = -143 ± 11 J mol-1 K-1, and ΔG‡ = 59.8 kJ mol-1 at 293 K). Comparison of the PCET efficiency of these clusters emphasizes the relevance of reorganization energy in this process.
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Affiliation(s)
- Marie Bergner
- Institute of Inorganic Chemistry, Georg-August-University Göttingen, Tammannstr. 4, D-37077 Göttingen, Germany
| | - Sebastian Dechert
- Institute of Inorganic Chemistry, Georg-August-University Göttingen, Tammannstr. 4, D-37077 Göttingen, Germany
| | - Serhiy Demeshko
- Institute of Inorganic Chemistry, Georg-August-University Göttingen, Tammannstr. 4, D-37077 Göttingen, Germany
| | - Claudia Kupper
- Institute of Inorganic Chemistry, Georg-August-University Göttingen, Tammannstr. 4, D-37077 Göttingen, Germany
| | - James M. Mayer
- Yale University, 225 Prospect Street, New Haven, Connecticut 06511, USA
| | - Franc Meyer
- Institute of Inorganic Chemistry, Georg-August-University Göttingen, Tammannstr. 4, D-37077 Göttingen, Germany
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78
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Atkinson JT, Campbell I, Bennett GN, Silberg JJ. Cellular Assays for Ferredoxins: A Strategy for Understanding Electron Flow through Protein Carriers That Link Metabolic Pathways. Biochemistry 2016; 55:7047-7064. [DOI: 10.1021/acs.biochem.6b00831] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joshua T. Atkinson
- Systems,
Synthetic, and Physical Biology Graduate Program, Rice University, MS-180, 6100 Main Street, Houston, Texas 77005, United States
| | - Ian Campbell
- Biochemistry
and Cell Biology Graduate Program, Rice University, MS-140, 6100
Main Street, Houston, Texas 77005, United States
| | - George N. Bennett
- Department
of Biosciences, Rice University, MS-140, 6100 Main Street, Houston, Texas 77005, United States
- Department
of Chemical and Biomolecular Engineering, Rice University, MS-362,
6100 Main Street, Houston, Texas 77005, United States
| | - Jonathan J. Silberg
- Department
of Biosciences, Rice University, MS-140, 6100 Main Street, Houston, Texas 77005, United States
- Department
of Bioengineering, Rice University, MS-142, 6100 Main Street, Houston, Texas 77005, United States
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79
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Holm RH, Lo W. Structural Conversions of Synthetic and Protein-Bound Iron–Sulfur Clusters. Chem Rev 2016; 116:13685-13713. [DOI: 10.1021/acs.chemrev.6b00276] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R. H. Holm
- Department
of Chemistry and
Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Wayne Lo
- Department
of Chemistry and
Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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80
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A Regulatory Circuit Composed of a Transcription Factor, IscR, and a Regulatory RNA, RyhB, Controls Fe-S Cluster Delivery. mBio 2016; 7:mBio.00966-16. [PMID: 27651365 PMCID: PMC5040110 DOI: 10.1128/mbio.00966-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Fe-S clusters are cofactors conserved through all domains of life. Once assembled by dedicated ISC and/or SUF scaffolds, Fe-S clusters are conveyed to their apo-targets via A-type carrier proteins (ATCs). Escherichia coli possesses four such ATCs. ErpA is the only ATC essential under aerobiosis. Recent studies reported a possible regulation of the erpA mRNA by the small RNA (sRNA) RyhB, which controls the expression of many genes under iron starvation. Surprisingly, erpA has not been identified in recent transcriptomic analysis of the iron starvation response, thus bringing into question the actual physiological significance of the putative regulation of erpA by RyhB. Using an sRNA library, we show that among 26 sRNAs, only RyhB represses the expression of an erpA-lacZ translational fusion. We further demonstrate that this repression occurs during iron starvation. Using mutational analysis, we show that RyhB base pairs to the erpA mRNA, inducing its disappearance. In addition, IscR, the master regulator of Fe-S homeostasis, represses expression of erpA at the transcriptional level when iron is abundant, but depleting iron from the medium alleviates this repression. The conjunction of transcriptional derepression by IscR and posttranscriptional repression by RyhB under Fe-limiting conditions is best described as an incoherent regulatory circuit. This double regulation allows full expression of erpA at iron concentrations for which Fe-S biogenesis switches from the ISC to the SUF system. We further provide evidence that this regulatory circuit coordinates ATC usage to iron availability. Regulatory small RNAs (sRNAs) have emerged as major actors in the control of gene expression in the last few decades. Relatively little is known about how these regulators interact with classical transcription factors to coordinate genetic responses. We show here how an sRNA, RyhB, and a transcription factor, IscR, regulate expression of an essential gene, erpA, in the bacterium E. coli. ErpA is involved in the biogenesis of Fe-S clusters, an important class of cofactors involved in a plethora of cellular reactions. Interestingly, we show that RyhB and IscR repress expression of erpA under opposite conditions in regard to iron concentration, forming a regulatory circuit called an “incoherent network.” This incoherent network serves to maximize expression of erpA at iron concentrations where it is most needed. Altogether, our study paves the way for a better understanding of mixed regulatory networks composed of RNAs and transcription factors.
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81
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Buzas DM. Emerging links between iron-sulfur clusters and 5-methylcytosine base excision repair in plants. Genes Genet Syst 2016; 91:51-62. [PMID: 27592684 DOI: 10.1266/ggs.16-00015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Iron-sulfur (Fe-S) clusters are ancient cofactors present in all kingdoms of life. Both the Fe-S cluster assembly machineries and target apoproteins are distributed across different subcellular compartments. The essential function of Fe-S clusters in nuclear enzymes is particularly difficult to study. The base excision repair (BER) pathway guards the integrity of DNA; enzymes from the DEMETER family of DNA glycosylases in plants are Fe-S cluster-dependent and extend the BER repertowere to excision of 5-methylcytosine (5mC). Recent studies in plants genetically link the majority of proteins from the cytosolic Fe-S cluster biogenesis (CIA) pathway with 5mC BER and DNA repair. This link can now be further explored. First, it opens new possibilities for understanding how Fe-S clusters participate in 5mC BER and related processes. I describe DNA-mediated charge transfer, an Fe-S cluster-based mechanism for locating base lesions with high efficiency, which is used by bacterial DNA glycosylases encoding Fe-S cluster binding domains that are also conserved in the DEMETER family. Second, because detailed analysis of the mutant phenotype of CIA proteins relating to 5mC BER revealed that they formed two groups, we may also gain new insights into both the composition of the Fe-S assembly pathway and the biological contexts of Fe-S proteins.
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Affiliation(s)
- Diana Mihaela Buzas
- Faculty of Life and Environmental Sciences, Gene Research Center, University of Tsukuba
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82
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Abstract
Iron-sulfur (Fe-S) clusters are fundamental to numerous biological processes in most organisms, but these protein cofactors can be prone to damage by various oxidants (e.g., O2, reactive oxygen species, and reactive nitrogen species) and toxic levels of certain metals (e.g., cobalt and copper). Furthermore, their synthesis can also be directly influenced by the level of available iron in the environment. Consequently, the cellular need for Fe-S cluster biogenesis varies with fluctuating growth conditions. To accommodate changes in Fe-S demand, microorganisms employ diverse regulatory strategies to tailor Fe-S cluster biogenesis according to their surroundings. Here, we review the mechanisms that regulate Fe-S cluster formation in bacteria, primarily focusing on control of the Isc and Suf Fe-S cluster biogenesis systems in the model bacterium Escherichia coli.
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Affiliation(s)
- Erin L Mettert
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, ,
| | - Patricia J Kiley
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, ,
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83
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Jelen BI, Giovannelli D, Falkowski PG. The Role of Microbial Electron Transfer in the Coevolution of the Biosphere and Geosphere. Annu Rev Microbiol 2016; 70:45-62. [PMID: 27297124 DOI: 10.1146/annurev-micro-102215-095521] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
All life on Earth is dependent on biologically mediated electron transfer (i.e., redox) reactions that are far from thermodynamic equilibrium. Biological redox reactions originally evolved in prokaryotes and ultimately, over the first ∼2.5 billion years of Earth's history, formed a global electronic circuit. To maintain the circuit on a global scale requires that oxidants and reductants be transported; the two major planetary wires that connect global metabolism are geophysical fluids-the atmosphere and the oceans. Because all organisms exchange gases with the environment, the evolution of redox reactions has been a major force in modifying the chemistry at Earth's surface. Here we briefly review the discovery and consequences of redox reactions in microbes with a specific focus on the coevolution of life and geochemical phenomena.
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Affiliation(s)
- Benjamin I Jelen
- Environmental Biophysics and Molecular Ecology Program, Institute of Earth, Ocean and Atmospheric Sciences, Rutgers University, New Brunswick, New Jersey 08901; , ,
| | - Donato Giovannelli
- Environmental Biophysics and Molecular Ecology Program, Institute of Earth, Ocean and Atmospheric Sciences, Rutgers University, New Brunswick, New Jersey 08901; , , .,Institute of Marine Science, National Research Council, 60125 Ancona, Italy.,Program in Interdisciplinary Studies, Institute for Advanced Studies, Princeton, New Jersey 08540.,Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan 152-8550
| | - Paul G Falkowski
- Environmental Biophysics and Molecular Ecology Program, Institute of Earth, Ocean and Atmospheric Sciences, Rutgers University, New Brunswick, New Jersey 08901; , , .,Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, New Jersey 08854
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84
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Fehl C, Davis BG. Proteins as templates for complex synthetic metalloclusters: towards biologically programmed heterogeneous catalysis. Proc Math Phys Eng Sci 2016; 472:20160078. [PMID: 27279776 PMCID: PMC4893187 DOI: 10.1098/rspa.2016.0078] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Despite nature's prevalent use of metals as prosthetics to adapt or enhance the behaviour of proteins, our ability to programme such architectural organization remains underdeveloped. Multi-metal clusters buried in proteins underpin the most remarkable chemical transformations in nature, but we are not yet in a position to fully mimic or exploit such systems. With the advent of copious, relevant structural information, judicious mechanistic studies and the use of accessible computational methods in protein design coupled with new synthetic methods for building biomacromolecules, we can envisage a 'new dawn' that will allow us to build de novo metalloenzymes that move beyond mono-metal centres. In particular, we highlight the need for systems that approach the multi-centred clusters that have evolved to couple electron shuttling with catalysis. Such hybrids may be viewed as exciting mid-points between homogeneous and heterogeneous catalysts which also exploit the primary benefits of biocatalysis.
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Affiliation(s)
- Charlie Fehl
- Department of Chemistry , University of Oxford , Oxford OX1 3TA, UK
| | - Benjamin G Davis
- Department of Chemistry , University of Oxford , Oxford OX1 3TA, UK
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85
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Aussignargues C, Pandelia ME, Sutter M, Plegaria JS, Zarzycki J, Turmo A, Huang J, Ducat DC, Hegg EL, Gibney BR, Kerfeld CA. Structure and Function of a Bacterial Microcompartment Shell Protein Engineered to Bind a [4Fe-4S] Cluster. J Am Chem Soc 2016; 138:5262-70. [PMID: 26704697 DOI: 10.1021/jacs.5b11734] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bacterial microcompartments (BMCs) are self-assembling organelles composed of a selectively permeable protein shell and encapsulated enzymes. They are considered promising templates for the engineering of designed bionanoreactors for biotechnology. In particular, encapsulation of oxidoreductive reactions requiring electron transfer between the lumen of the BMC and the cytosol relies on the ability to conduct electrons across the shell. We determined the crystal structure of a component protein of a synthetic BMC shell, which informed the rational design of a [4Fe-4S] cluster-binding site in its pore. We also solved the structure of the [4Fe-4S] cluster-bound, engineered protein to 1.8 Å resolution, providing the first structure of a BMC shell protein containing a metal center. The [4Fe-4S] cluster was characterized by optical and EPR spectroscopies; it has a reduction potential of -370 mV vs the standard hydrogen electrode (SHE) and is stable through redox cycling. This remarkable stability may be attributable to the hydrogen-bonding network provided by the main chain of the protein scaffold. The properties of the [4Fe-4S] cluster resemble those in low-potential bacterial ferredoxins, while its ligation to three cysteine residues is reminiscent of enzymes such as aconitase and radical S-adenosymethionine (SAM) enzymes. This engineered shell protein provides the foundation for conferring electron-transfer functionality to BMC shells.
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Affiliation(s)
| | - Maria-Eirini Pandelia
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Markus Sutter
- Physical Biosciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | | | | | | | | | | | | | - Brian R Gibney
- Department of Chemistry, Brooklyn College , Brooklyn, New York 11210, United States
- Ph.D. Programs in Chemistry and Biochemistry, The Graduate Center of the City University of New York , New York, New York 10016, United States
| | - Cheryl A Kerfeld
- Physical Biosciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Department of Plant and Microbial Biology, University of California , Berkeley, California 94720, United States
- Berkeley Synthetic Biology Institute , Berkeley, California 94720, United States
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86
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Kowalska JK, Hahn AW, Albers A, Schiewer CE, Bjornsson R, Lima FA, Meyer F, DeBeer S. X-ray Absorption and Emission Spectroscopic Studies of [L2Fe2S2](n) Model Complexes: Implications for the Experimental Evaluation of Redox States in Iron-Sulfur Clusters. Inorg Chem 2016; 55:4485-97. [PMID: 27097289 PMCID: PMC5108557 DOI: 10.1021/acs.inorgchem.6b00295] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein, a systematic study of [L2Fe2S2](n) model complexes (where L = bis(benzimidazolato) and n = 2-, 3-, 4-) has been carried out using iron and sulfur K-edge X-ray absorption (XAS) and iron Kβ and valence-to-core X-ray emission spectroscopies (XES). These data are used as a test set to evaluate the relative strengths and weaknesses of X-ray core level spectroscopies in assessing redox changes in iron-sulfur clusters. The results are correlated to density functional theory (DFT) calculations of the spectra in order to further support the quantitative information that can be extracted from the experimental data. It is demonstrated that due to canceling effects of covalency and spin state, the information that can be extracted from Fe Kβ XES mainlines is limited. However, a careful analysis of the Fe K-edge XAS data shows that localized valence vs delocalized valence species may be differentiated on the basis of the pre-edge and K-edge energies. These findings are then applied to existing literature Fe K-edge XAS data on the iron protein, P-cluster, and FeMoco sites of nitrogenase. The ability to assess the extent of delocalization in the iron protein vs the P-cluster is highlighted. In addition, possible charge states for FeMoco on the basis of Fe K-edge XAS data are discussed. This study provides an important reference for future X-ray spectroscopic studies of iron-sulfur clusters.
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Affiliation(s)
- Joanna K Kowalska
- Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Anselm W Hahn
- Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Antonia Albers
- Institute of Inorganic Chemistry, Georg-August-University Göttingen , Tammannstraße 4, D-37077 Göttingen, Germany
| | - Christine E Schiewer
- Institute of Inorganic Chemistry, Georg-August-University Göttingen , Tammannstraße 4, D-37077 Göttingen, Germany
| | - Ragnar Bjornsson
- Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Frederico A Lima
- Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Franc Meyer
- Institute of Inorganic Chemistry, Georg-August-University Göttingen , Tammannstraße 4, D-37077 Göttingen, Germany
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36, D-45470 Mülheim an der Ruhr, Germany.,Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
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87
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Popovic M, Pastore A. Chemical shift assignment of the alternative scaffold protein IscA. BIOMOLECULAR NMR ASSIGNMENTS 2016; 10:227-231. [PMID: 26887894 PMCID: PMC4788688 DOI: 10.1007/s12104-016-9672-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 02/05/2016] [Indexed: 06/05/2023]
Abstract
The IscA protein (11.5 kDa) is an essential component of the iron sulphur cluster biogenesis machine. In bacteria, the machine components are clustered in operons, amongst which the most important is the isc operon. Bacterial IscA has direct homologues also in eukaryotes. Like the protein IscU, IscA is thought to assist cluster formation as an alternative scaffold protein which receives the cluster before transferring it further to the final acceptors. Several crystal structures have been published. They all report an IscA dimeric form, although the packing of the protomers in the dimers differs amongst structures. No solution studies have currently been reported. Here we report the (1)H, (13)C and (15)N backbone and side-chain chemical shift assignments of the cluster-free E. coli IscA as a starting point for further studies of the structure and functions of this still poorly characterized protein. We show that IscA exists in solution as an equilibrium between different species. Spectrum assignment was thus challenging given the heterogeneous nature of the sample but doable through judicious choice of selective labelling and concentration dependent studies.
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Affiliation(s)
- Matija Popovic
- Maurice Wohl Institute, King's College London, 5 Cutcombe Rd., London, SE5 9RT, UK
| | - Annalisa Pastore
- Maurice Wohl Institute, King's College London, 5 Cutcombe Rd., London, SE5 9RT, UK.
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88
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Survival Strategies of the Plant-Associated Bacterium Enterobacter sp. Strain EG16 under Cadmium Stress. Appl Environ Microbiol 2016; 82:1734-1744. [PMID: 26729719 DOI: 10.1128/aem.03689-15] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 12/29/2015] [Indexed: 11/20/2022] Open
Abstract
Plant-associated bacteria are of great interest because of their potential use in phytoremediation. However, their ability to survive and promote plant growth in metal-polluted soils remains unclear. In this study, a soilborne Cd-resistant bacterium was isolated and identified as Enterobacter sp. strain EG16. It tolerates high external Cd concentrations (Cd(2+) MIC, >250 mg liter(-1)) and is able to produce siderophores and the plant hormone indole-3-acetic acid (IAA), both of which contribute to plant growth promotion. Surface biosorption in this strain accounted for 31% of the total Cd accumulated. The potential presence of cadmium sulfide, shown by energy-dispersive X-ray (EDX) analysis, suggested intracellular Cd binding as a Cd response mechanism of the isolate. Cd exposure resulted in global regulation at the transcriptomic level, with the bacterium switching to an energy-conserving mode by inhibiting energy-consuming processes while increasing the production of stress-related proteins. The stress response system included increased import of sulfur and iron, which become deficient under Cd stress, and the redirection of sulfur metabolism to the maintenance of intracellular glutathione levels in response to Cd toxicity. Increased production of siderophores, responding to Cd-induced Fe deficiency, not only is involved in the Cd stress response systems of EG16 but may also play an important role in promoting plant growth as well as alleviating the Cd-induced inhibition of IAA production. The newly isolated strain EG16 may be a suitable candidate for microbially assisted phytoremediation due to its high resistance to Cd and its Cd-induced siderophore production, which is likely to contribute to plant growth promotion.
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89
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Tanaka N, Kanazawa M, Tonosaki K, Yokoyama N, Kuzuyama T, Takahashi Y. Novel features of the ISC machinery revealed by characterization of Escherichia coli mutants that survive without iron-sulfur clusters. Mol Microbiol 2015; 99:835-48. [PMID: 26560204 DOI: 10.1111/mmi.13271] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2015] [Indexed: 01/09/2023]
Abstract
Biological assembly of iron-sulfur (Fe-S) clusters is mediated by complex systems consisting of multiple proteins. Escherichia coli possesses two distinct systems called the ISC and SUF machineries encoded by iscSUA-hscBA-fdx-iscX and sufABCDSE respectively. Deletion of both pathways results in absence of the biosynthetic apparatus for Fe-S clusters, and consequent lethality, which has hampered detailed genetic studies. Here we report that modification of the isoprenoid biosynthetic pathway can offset the indispensability of the Fe-S cluster biosynthetic systems and show that the resulting Δisc Δsuf double mutants can grow without detectable Fe-S cluster-containing proteins. We also constructed a series of mutants in which each isc gene was disrupted in the deletion background of sufABCDSE. Phenotypic analysis of the mutants revealed that Fdx, an essential electron-transfer Fe-S protein in the ISC machinery, is dispensable under anaerobic conditions, which is similar to the situation with IscA. Furthermore, we found that several suppressor mutations in IscU, an Fe-S scaffold protein responsible for the de novo Fe-S cluster assembly, could bypass the essential role of the chaperone system HscA and HscB. These findings pave the way toward a detailed molecular analysis to understand the mechanisms involved in Fe-S cluster biosynthesis.
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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
| | - Miaki Kanazawa
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Keitaro Tonosaki
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Nao Yokoyama
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Tomohisa Kuzuyama
- Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, 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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90
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Abstract
This review describes the two main systems, namely the Isc (iron-sulfur cluster) and Suf (sulfur assimilation) systems, utilized by Escherichia coli and Salmonella for the biosynthesis of iron-sulfur (Fe-S) clusters, as well as other proteins presumably participating in this process. In the case of Fe-S cluster biosynthesis, it is assumed that the sulfur atoms from the cysteine desulfurase end up at cysteine residues of the scaffold protein, presumably waiting for iron atoms for cluster assembly. The review discusses the various potential iron donor proteins. For in vitro experiments, in general, ferrous salts are used during the assembly of Fe-S clusters, even though this approach is unlikely to reflect the physiological conditions. The fact that sulfur atoms can be directly transferred from cysteine desulfurases to scaffold proteins supports a mechanism in which the latter bind sulfur atoms first and iron atoms afterwards. In E. coli, fdx gene inactivation results in a reduced growth rate and reduced Fe-S enzyme activities. Interestingly, the SufE structure resembles that of IscU, strengthening the notion that the two proteins share the property of acting as acceptors of sulfur atoms provided by cysteine desulfurases. Several other factors have been suggested to participate in cluster assembly and repair in E. coli and Salmonella. Most of them were identified by their abilities to act as extragenic and/or multicopy suppressors of mutations in Fe-S cluster metabolism, while others possess biochemical properties that are consistent with a role in Fe-S cluster biogenesis.
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91
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Yan Y, Grant GA, Gross ML. Hydrogen-Deuterium Exchange Mass Spectrometry Reveals Unique Conformational and Chemical Transformations Occurring upon [4Fe-4S] Cluster Binding in the Type 2 L-Serine Dehydratase from Legionella pneumophila. Biochemistry 2015; 54:5322-8. [PMID: 26266572 DOI: 10.1021/acs.biochem.5b00761] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The type 2 L-serine dehydratase from Legionella pneumophila (lpLSD) contains a [4Fe-4S](2+) cluster that acts as a Lewis acid to extract the hydroxyl group of L-serine during the dehydration reaction. Surprisingly, the crystal structure shows that all four of the iron atoms in the cluster are coordinated with protein cysteinyl residues and that the cluster is buried and not exposed to solvent. If the crystal structure of lpLSD accurately reflects the structure in solution, then substantial rearrangement at the active site is necessary for the substrate to enter. Furthermore, repair of the oxidized protein when the cluster has degraded would presumably entail exposure of the buried cysteine ligands. Thus, the conformation required for the substrate to enter may be similar to those required for a new cluster to enter the active site. To address this, hydrogen-deuterium exchange combined with mass spectrometry (HDX MS) was used to probe the conformational changes that occur upon oxidative degradation of the Fe-S cluster. The regions that show the most significant differential HDX are adjacent to the cluster location in the holoenzyme or connect regions that are adjacent to the cluster. The observed decrease in flexibility upon cluster binding provides direct evidence that the "tail-in-mouth" conformation observed in the crystal structure also occurs in solution and that the C-terminal peptide is coordinated to the [4Fe-4S] cluster in a precatalytic conformation. This observation is consistent with the requirement of an activation step prior to catalysis and the unusually high level of resistance to oxygen-induced cluster degradation. Furthermore, peptide mapping of the apo form under nonreducing conditions revealed the formation of disulfide bonds between C396 and C485 and possibly between C343 and C385. These observations provide a picture of how the cluster loci are stabilized and poised to receive the cluster in the apo form and the requirement for a reduction step during cluster formation.
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Affiliation(s)
- Yuetian Yan
- Department of Chemistry, Washington University , One Brookings Drive, Box 1134, St. Louis, Missouri 63130, United States
| | - Gregory A Grant
- Department of Developmental Biology and Department of Medicine, Washington University School of Medicine , 660 South Euclid Avenue, Box 8103, St. Louis, Missouri 63110, United States
| | - Michael L Gross
- Department of Chemistry, Washington University , One Brookings Drive, Box 1134, St. Louis, Missouri 63130, United States
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92
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Remes B, Eisenhardt BD, Srinivasan V, Klug G. IscR of Rhodobacter sphaeroides functions as repressor of genes for iron-sulfur metabolism and represents a new type of iron-sulfur-binding protein. Microbiologyopen 2015; 4:790-802. [PMID: 26235649 PMCID: PMC4618611 DOI: 10.1002/mbo3.279] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 06/15/2015] [Accepted: 06/23/2015] [Indexed: 12/20/2022] Open
Abstract
IscR proteins are known as transcriptional regulators for Fe–S biogenesis. In the facultatively phototrophic bacterium, Rhodobacter sphaeroides IscR is the product of the first gene in the isc-suf operon. A major role of IscR in R. sphaeroides iron-dependent regulation was suggested in a bioinformatic study (Rodionov et al., PLoS Comput Biol 2:e163, 2006), which predicted a binding site in the upstream regions of several iron uptake genes, named Iron-Rhodo-box. Most known IscR proteins have Fe–S clusters featuring (Cys)3(His)1 ligation. However, IscR proteins from Rhodobacteraceae harbor only a single-Cys residue and it was considered unlikely that they can ligate an Fe–S cluster. In this study, the role of R. sphaeroides IscR as transcriptional regulator and sensor of the Fe–S cluster status of the cell was analyzed. A mutant lacking IscR is more impaired in growth under iron limitation than the wild-type and exhibits significantly increased ROS levels in iron-replete and iron-deplete conditions. Expression studies reveal that R. sphaeroides IscR in its cluster-bound form functions as transcriptional repressor of genes involved in iron metabolism by direct binding to the promoter region of genes preceded by the motif. A total of 110 genes are directly or indirectly affected by IscR. Furthermore, IscR possesses a unique Fe–S cluster ligation scheme with only a single cysteine involved.
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Affiliation(s)
- Bernhard Remes
- Institut für Mikrobiologie und Molekularbiologie, IFZ, Justus-Liebig-Universität, 35392, Giessen, Germany
| | - Benjamin D Eisenhardt
- Institut für Mikrobiologie und Molekularbiologie, IFZ, Justus-Liebig-Universität, 35392, Giessen, Germany
| | - Vasundara Srinivasan
- LOEWE-Zentrum für Synthetische Mikrobiologie, Philipps Universität Marburg, 35043, Marburg, Germany
| | - Gabriele Klug
- Institut für Mikrobiologie und Molekularbiologie, IFZ, Justus-Liebig-Universität, 35392, Giessen, Germany
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93
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Paritala H, Suzuki Y, Carroll KS. Design, synthesis and evaluation of Fe-S targeted adenosine 5'-phosphosulfate reductase inhibitors. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2015; 34:199-220. [PMID: 25710356 DOI: 10.1080/15257770.2014.978012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Adenosine 5'-phosphosulfate reductase (APR) is an iron-sulfur enzyme that is vital for survival of Mycobacterium tuberculosis during dormancy and is an attractive target for the treatment of latent tuberculosis (TB) infection. The 4Fe-4S cluster is coordinated to APR by sulfur atoms of four cysteine residues, is proximal to substrate, adenosine 5'-phopsphosulfate (APS), and is essential for catalytic activity. Herein, we present an approach for the development of a new class of APR inhibitors. As an initial step, we have employed an improved solid-phase chemistry method to prepare a series of N(6)-substituted adenosine analogues and their 5'-phosphates as well as adenosine 5'-phosphate diesters bearing different Fe and S binding groups, such as thiols or carboxylic and hydroxamic acid moieties. Evaluation of the resulting compounds indicates a clearly defined spacing requirement between the Fe-S targeting group and adenosine scaffold and that smaller Fe-S targeting groups are better tolerated. Molecular docking analysis suggests that the S atom of the most potent inhibitor may establish a favorable interaction with an S atom in the cluster. In summary, this study showcases an improved solid-phase method that expedites the preparation of adenosine and related 5'-phosphate derivatives and presents a unique Fe-S targeting strategy for the development of APR inhibitors.
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94
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Reesbeck ME, Rodriguez MM, Brennessel WW, Mercado BQ, Vinyard D, Holland PL. Oxidized and reduced [2Fe-2S] clusters from an iron(I) synthon. J Biol Inorg Chem 2015; 20:875-83. [PMID: 26044124 DOI: 10.1007/s00775-015-1272-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 05/20/2015] [Indexed: 02/06/2023]
Abstract
Synthetic [2Fe-2S] clusters are often used to elucidate ligand effects on the reduction potentials and spectroscopy of natural electron-transfer sites, which can have anionic Cys ligands or neutral His ligands. Current synthetic routes to [2Fe-2S] clusters are limited in their feasibility with a range of supporting ligands. Here, we report a new synthetic route to synthetic [2Fe-2S] clusters, through oxidation of an iron(I) source with elemental sulfur. This method yields a neutral diketiminate-supported [2Fe-2S] cluster in the diiron(III)-oxidized form. The oxidized [2Fe-2S] cluster can be reduced to a mixed valent iron(II)-iron(III) compound. Both the diferric and reduced mixed valent clusters are characterized using X-ray crystallography, Mössbauer spectroscopy, EPR spectroscopy and cyclic voltammetry. The reduced compound is particularly interesting because its X-ray crystal structure shows a difference in Fe-S bond lengths to one of the iron atoms, consistent with valence localization. The valence localization is also evident from Mössbauer spectroscopy.
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Affiliation(s)
- Megan E Reesbeck
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, 06520, USA
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95
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Fuss JO, Tsai CL, Ishida JP, Tainer JA. Emerging critical roles of Fe-S clusters in DNA replication and repair. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1853:1253-71. [PMID: 25655665 PMCID: PMC4576882 DOI: 10.1016/j.bbamcr.2015.01.018] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 01/13/2015] [Accepted: 01/26/2015] [Indexed: 10/24/2022]
Abstract
Fe-S clusters are partners in the origin of life that predate cells, acetyl-CoA metabolism, DNA, and the RNA world. The double helix solved the mystery of DNA replication by base pairing for accurate copying. Yet, for genome stability necessary to life, the double helix has equally important implications for damage repair. Here we examine striking advances that uncover Fe-S cluster roles both in copying the genetic sequence by DNA polymerases and in crucial repair processes for genome maintenance, as mutational defects cause cancer and degenerative disease. Moreover, we examine an exciting, controversial role for Fe-S clusters in a third element required for life - the long-range coordination and regulation of replication and repair events. By their ability to delocalize electrons over both Fe and S centers, Fe-S clusters have unbeatable features for protein conformational control and charge transfer via double-stranded DNA that may fundamentally transform our understanding of life, replication, and repair. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- Jill O Fuss
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
| | - Chi-Lin Tsai
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Justin P Ishida
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - John A Tainer
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA; Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA.
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96
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The ferrous iron-responsive BqsRS two-component system activates genes that promote cationic stress tolerance. mBio 2015; 6:e02549. [PMID: 25714721 PMCID: PMC4358008 DOI: 10.1128/mbio.02549-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
UNLABELLED The physiological resistance of pathogens to antimicrobial treatment is a severe problem in the context of chronic infections. For example, the mucus-filled lungs of cystic fibrosis (CF) patients are readily colonized by diverse antibiotic-resistant microorganisms, including Pseudomonas aeruginosa. Previously, we showed that bioavailable ferrous iron [Fe(II)] is present in CF sputum at all stages of infection and constitutes a significant portion of the iron pool at advanced stages of lung function decline [R. C. Hunter et al., mBio 4(4):e00557-13, 2013]. P. aeruginosa, a dominant CF pathogen, senses Fe(II) using a two-component signal transduction system, BqsRS, which is transcriptionally active in CF sputum [R. C. Hunter et al., mBio 4(4):e00557-13, 2013; N. N. Kreamer, J. C. Wilks, J. J. Marlow, M. L. Coleman, and D. K. Newman, J Bacteriol 194:1195-1204, 2012]. Here, we show that an RExxE motif in BqsS is required for BqsRS activation. Once Fe(II) is sensed, BqsR binds a tandem repeat DNA sequence, activating transcription. The BqsR regulon--defined through iterative bioinformatic predictions and experimental validation--includes several genes whose products are known to drive antibiotic resistance to aminoglycosides and polymyxins. Among them are genes encoding predicted determinants of polyamine transport and biosynthesis. Compared to the wild type, bqsS and bqsR deletion mutants are sensitive to high levels of Fe(II), produce less spermidine in high Fe(II), and are more sensitive to tobramycin and polymyxin B but not arsenate, chromate, or cefsulodin. BqsRS thus mediates a physiological response to Fe(II) that guards the cell against positively charged molecules but not negatively charged stressors. These results suggest Fe(II) is an important environmental signal that, via BqsRS, bolsters tolerance of a variety of cationic stressors, including clinically important antimicrobial agents. IMPORTANCE Clearing chronic infections is challenging due to the physiological resistance of opportunistic pathogens to antibiotics. Effective treatments are hindered by a lack of understanding of how these organisms survive in situ. Fe(II) is typically present at micromolar levels in soils and sedimentary habitats, as well as in CF sputum. All P. aeruginosa strains possess a two-component system, BqsRS, that specifically senses extracellular Fe(II) at low micromolar concentrations. Our work shows that BqsRS protects the cell against cationic perturbations to the cell envelope as well as low pH and reduction potential (Eh), conditions under which Fe(2+) is stable. Fe(II) can thus be understood as a proxy for a broader environmental state; the cellular response to its detection may help rationalize the resistance of P. aeruginosa to clinically important cationic antibiotics. This finding demonstrates the importance of considering environmental chemistry when exploring mechanisms of microbial survival in habitats that include the human body.
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97
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Py B, Barras F. [Iron and sulfur in proteins. How does the cell build Fe-S clusters, cofactors essential for life?]. Med Sci (Paris) 2014; 30:1110-22. [PMID: 25537041 DOI: 10.1051/medsci/20143012014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Iron-sulfur clusters (Fe-S) are ubiquitous cofactors present in numerous proteins of most living organisms. By way of an example, the E. coli bacterium synthesizes more that 130 different types of Fe-S proteins. Fe-S proteins are involved in a great diversity of biological processes, ranging from respiration, photosynthesis, central metabolism, to genetic expression and genomic stability. Proteins can acquire spontaneously Fe-S clusters in vitro, but in vivo, dedicated molecular machineries are necessary. Dysfunction of these machineries alters cellular capacities leading to lethality in bacteria and severe pathologies in humans. In this review we will describe how cells make Fe-S clusters and deliver them to clients proteins. The importance of Fe-S clusters homeostasis will be illustrated by reporting a list of cellular dysfunctions associated with mutations altering either Fe-S proteins or Fe-S biogenesis machineries.
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Affiliation(s)
- Béatrice Py
- Laboratoire de Chimie Bactérienne, UMR 7283 CNRS-Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, 31, chemin Joseph Aiguier, 13009 Marseille, France
| | - Frédéric Barras
- Laboratoire de Chimie Bactérienne, UMR 7283 CNRS-Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, 31, chemin Joseph Aiguier, 13009 Marseille, France
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98
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Zimmerman MT, Bayse CA, Ramoutar RR, Brumaghim JL. Sulfur and selenium antioxidants: challenging radical scavenging mechanisms and developing structure-activity relationships based on metal binding. J Inorg Biochem 2014; 145:30-40. [PMID: 25600984 DOI: 10.1016/j.jinorgbio.2014.12.020] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 12/17/2014] [Accepted: 12/19/2014] [Indexed: 11/30/2022]
Abstract
Because sulfur and selenium antioxidants can prevent oxidative damage, numerous animal and clinical trials have investigated the ability of these compounds to prevent the oxidative stress that is an underlying cause of cardiovascular disease, Alzheimer's disease, and cancer, among others. One of the most common sources of oxidative damage is metal-generated hydroxyl radical; however, very little research has focused on determining the metal-binding abilities and structural attributes that affect oxidative damage prevention by sulfur and selenium compounds. In this review, we describe our ongoing investigations into sulfur and selenium antioxidant prevention of iron- and copper-mediated oxidative DNA damage. We determined that many sulfur and selenium compounds inhibit Cu(I)-mediated DNA damage and that DNA damage prevention varies dramatically when Fe(II) is used in place of Cu(I) to generate hydroxyl radical. Oxidation potentials of the sulfur or selenium compounds do not correlate with their ability to prevent DNA damage, highlighting the importance of metal coordination rather than reactive oxygen species scavenging as an antioxidant mechanism. Additional gel electrophoresis, mass spectrometry, and UV-visible studies confirmed sulfur and selenium antioxidant binding to Cu(I) and Fe(II). Ultimately, our studies established that both the hydroxyl-radical-generating metal ion and the chemical environment of the sulfur or selenium significantly affect DNA damage prevention and that metal coordination is an essential mechanism for these antioxidants.
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Affiliation(s)
| | - Craig A Bayse
- Department of Chemistry and Biochemistry, Old Dominion University, Hampton Boulevard, Norfolk, VA 23529, USA
| | - Ria R Ramoutar
- Department of Chemistry, Clemson University, Clemson, SC 29634-0973, USA
| | - Julia L Brumaghim
- Department of Chemistry, Clemson University, Clemson, SC 29634-0973, USA.
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99
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Blanc B, Gerez C, Ollagnier de Choudens S. Assembly of Fe/S proteins in bacterial systems: Biochemistry of the bacterial ISC system. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1436-47. [PMID: 25510311 DOI: 10.1016/j.bbamcr.2014.12.009] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 11/20/2014] [Accepted: 12/08/2014] [Indexed: 12/26/2022]
Abstract
Iron/sulfur clusters are key cofactors in proteins involved in a large number of conserved cellular processes, including gene expression, DNA replication and repair, ribosome biogenesis, tRNA modification, central metabolism and respiration. Fe/S proteins can perform a wide range of functions, from electron transfer to redox and non-redox catalysis. In all living organisms, Fe/S proteins are first synthesized in an apo-form. However, as the Fe/S prosthetic group is required for correct folding and/or protein stability, Fe/S clusters are inserted co-translationally or immediately after translation by specific assembly machineries. These systems have been extensively studied over the last decade, both in prokaryotes and eukaryotes. The present review covers the basic principles of the bacterial housekeeping Fe/S biogenesis ISC system, and related recent molecular advances. Some of the most exciting recent highlights relating to this system include structural and functional characterization of binary and ternary complexes involved in Fe/S cluster formation on the scaffold protein IscU. These advances enhance our understanding of the Fe/S cluster assembly mechanism by revealing essential interactions that could never be determined with isolated proteins and likely are closer to an in vivo situation. Much less is currently known about the molecular mechanism of the Fe/S transfer step, but a brief account of the protein-protein interactions involved is given. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- B Blanc
- Université Grenoble Alpes, LCBM, 38054 Grenoble, France; CEA, DSV, iRTSV, LCBM, Biocatalyse, 38054 Grenoble, France; CNRS UMR5249, LCBM, 38054 Grenoble, France
| | - C Gerez
- Université Grenoble Alpes, LCBM, 38054 Grenoble, France; CEA, DSV, iRTSV, LCBM, Biocatalyse, 38054 Grenoble, France; CNRS UMR5249, LCBM, 38054 Grenoble, France
| | - S Ollagnier de Choudens
- Université Grenoble Alpes, LCBM, 38054 Grenoble, France; CEA, DSV, iRTSV, LCBM, Biocatalyse, 38054 Grenoble, France; CNRS UMR5249, LCBM, 38054 Grenoble, France.
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100
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Mettert EL, Kiley PJ. Fe-S proteins that regulate gene expression. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1284-93. [PMID: 25450978 DOI: 10.1016/j.bbamcr.2014.11.018] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 10/24/2014] [Accepted: 11/13/2014] [Indexed: 02/06/2023]
Abstract
Iron-sulfur (Fe-S) cluster containing proteins that regulate gene expression are present in most organisms. The innate chemistry of their Fe-S cofactors makes these regulatory proteins ideal for sensing environmental signals, such as gases (e.g. O2 and NO), levels of Fe and Fe-S clusters, reactive oxygen species, and redox cycling compounds, to subsequently mediate an adaptive response. Here we review the recent findings that have provided invaluable insight into the mechanism and function of these highly significant Fe-S regulatory proteins. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- Erin L Mettert
- University of Wisconsin-Madison, Department of Biomolecular Chemistry, 440 Henry Mall, Biochemical Sciences Building, Room 4204C, Madison, WI 53706, USA.
| | - Patricia J Kiley
- University of Wisconsin-Madison, Department of Biomolecular Chemistry, 440 Henry Mall, Biochemical Sciences Building, Room 4204C, Madison, WI 53706, USA.
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