Spin-symmetrised structures and vibrational frequencies of iron–sulfur clusters

2020 ◽  
Vol 22 (29) ◽  
pp. 16655-16664
Author(s):  
Francesco Cappelluti ◽  
Luigi Bencivenni ◽  
Leonardo Guidoni
Keyword(s):  
Vibrational Frequencies ◽  
Broken Symmetry ◽  
Vibrational Properties ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur Clusters ◽  
Sulfur Cluster ◽  
Iron Sulfur

The recently developed Extended Broken Symmetry technique is employed for studying a bi- and tetra-nuclear iron–sulfur cluster with respect to magnetic, structural and, most importantly, vibrational properties.

scholarly journals Multiple Sense and Antisense Promoters Contribute to the Regulated Expression of the isc-suf Operon for Iron-Sulfur Cluster Assembly in Rhodobacter

2019 ◽  
Vol 7 (12) ◽  
pp. 671 ◽  
Author(s):  
Xin Nie ◽  
Bernhard Remes ◽  
Gabriele Klug
Keyword(s):  
Rhodobacter Sphaeroides ◽  
Photosynthetic Electron Transport ◽  
Regulatory Proteins ◽  
Cluster Assembly ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur Clusters ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Photosynthetic Complexes ◽  
The One

A multitude of biological functions relies on iron-sulfur clusters. The formation of photosynthetic complexes goes along with an additional demand for iron-sulfur clusters for bacteriochlorophyll synthesis and photosynthetic electron transport. However, photooxidative stress leads to the destruction of iron-sulfur clusters, and the released iron promotes the formation of further reactive oxygen species. A balanced regulation of iron-sulfur cluster synthesis is required to guarantee the supply of this cofactor, on the one hand, but also to limit stress, on the other hand. The phototrophic alpha-proteobacterium Rhodobacter sphaeroides harbors a large operon for iron-sulfur cluster assembly comprising the iscRS and suf genes. IscR (iron-sulfur cluster regulator) is an iron-dependent regulator of isc-suf genes and other genes with a role in iron metabolism. We applied reporter gene fusions to identify promoters of the isc-suf operon and studied their activity alone or in combination under different conditions. Gel-retardation assays showed the binding of regulatory proteins to individual promoters. Our results demonstrated that several promoters in a sense and antisense direction influenced isc-suf expression and the binding of the IscR, Irr, and OxyR regulatory proteins to individual promoters. These findings demonstrated a complex regulatory network of several promoters and regulatory proteins that helped to adjust iron-sulfur cluster assembly to changing conditions in Rhodobacter sphaeroides.

scholarly journals Distinct Roles of the Salmonella enterica Serovar Typhimurium CyaY and YggX Proteins in the Biosynthesis and Repair of Iron-Sulfur Clusters

2014 ◽  
Vol 82 (4) ◽  
pp. 1390-1401 ◽  
Author(s):  
Jyoti Velayudhan ◽  
Joyce E. Karlinsey ◽  
Elaine R. Frawley ◽  
Lynne A. Becker ◽  
Margaret Nartea ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Salmonella Enterica ◽  
Active Sites ◽  
Nitrosative Stress ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur Clusters ◽  
Content Type ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Serovar Typhimurium

ABSTRACTLabile [4Fe-4S]2+clusters found at the active sites of many dehydratases are susceptible to damage by univalent oxidants that convert the clusters to an inactive [3Fe-4S]1+form. Bacteria repair damaged clusters in a process that does not requirede novoprotein synthesis or the Isc and Suf cluster assembly pathways. The current study investigates the participation of the bacterial frataxin ortholog CyaY and the YggX protein, which are proposed to play roles in iron trafficking and iron-sulfur cluster repair. Previous reports found that individual mutations incyaYoryggXwere not associated with phenotypic changes inEscherichia coliandSalmonella entericaserovar Typhimurium, suggesting that CyaY and YggX might have functionally redundant roles. However, we have found that individual mutations incyaYoryggXconfer enhanced susceptibility to hydrogen peroxide inSalmonella entericaserovar Typhimurium. In addition, inactivation of thestm3944open reading frame, which is located immediately upstream ofcyaYand which encodes a putative inner membrane protein, dramatically enhances the hydrogen peroxide sensitivity of acyaYmutant. Overexpression of STM3944 reduces the elevated intracellular free iron levels observed in anS. Typhimuriumfurmutant and also reduces the total cellular iron content under conditions of iron overload, suggesting that thestm3944-encoded protein may mediate iron efflux. Mutations incyaYandyggXhave different effects on the activities of the iron-sulfur cluster-containing aconitase, serine deaminase, and NADH dehydrogenase I enzymes ofS. Typhimurium under basal conditions or following recovery from oxidative stress. In addition,cyaYandyggXmutations have additive effects on 6-phosphogluconate dehydratase-dependent growth during nitrosative stress, and acyaYmutation reducesSalmonellavirulence in mice. Collectively, these results indicate that CyaY and YggX play distinct supporting roles in iron-sulfur cluster biosynthesis and the repair of labile clusters damaged by univalent oxidants.Salmonellaexperiences oxidative and nitrosative stress within host phagocytes, and CyaY-dependent maintenance of labile iron-sulfur clusters appears to be important forSalmonellavirulence.

Biogenesis and Transfer of Iron-Sulfur Clusters from Acidithiobacillus ferrooxidans

2013 ◽  
Vol 825 ◽  
pp. 198-201 ◽  
Author(s):  
Jian She Liu ◽  
Lin Qian ◽  
Chun Li Zheng
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Binding Protein ◽  
Cluster Assembly ◽  
Cysteine Desulfurase ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur Clusters ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Iron Sulfur Proteins

Iron-sulfur (Fe-S) proteins are ubiquitous and participate in multiple essential functions of life. However, little is currently known about the mechanisms of iron-sulfur biosynthesis and transfer in acidophilic microorganisms. In this study, the IscS, IscU and IscA proteins from Acidithiobacillus ferrooxidans were successfully expressed in Escherichia coli and purified by affinity chromatography. The IscS was a cysteine desulfurase which catalyzes desulfurization of L-cysteine and transfer sulfur for iron-sulfur cluster assembly. Purified IscU did not have an iron-sulfur cluster but could act as a scaffold protein to assemble the [2Fe-2S] cluster in vitro. The IscA was a [4Fe-4S] cluster binding protein, but it also acted as an iron binding protein. Further studies indicated that the iron sulfur clusters could be transferred from pre-assembled scaffold proteins to apo-form iron sulfur proteins, the reconstituted iron sulfur proteins could restore their physiological activities.

scholarly journals Modulation of MagR magnetic properties via iron–sulfur cluster binding

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhen Guo ◽  
Shuai Xu ◽  
Xue Chen ◽  
Changhao Wang ◽  
Peilin Yang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Host Proteins ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur Clusters ◽  
Environmental Signals ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Different Types ◽  
Intrinsic Magnetic Moment ◽  
Forms Of Iron

AbstractIron–sulfur clusters are essential cofactors found in all kingdoms of life and play essential roles in fundamental processes, including but not limited to respiration, photosynthesis, and nitrogen fixation. The chemistry of iron–sulfur clusters makes them ideal for sensing various redox environmental signals, while the physics of iron–sulfur clusters and its host proteins have been long overlooked. One such protein, MagR, has been proposed as a putative animal magnetoreceptor. It forms a rod-like complex with cryptochromes (Cry) and possesses intrinsic magnetic moment. However, the magnetism modulation of MagR remains unknown. Here in this study, iron–sulfur cluster binding in MagR has been characterized. Three conserved cysteines of MagR play different roles in iron–sulfur cluster binding. Two forms of iron–sulfur clusters binding have been identified in pigeon MagR and showed different magnetic properties: [3Fe–4S]-MagR appears to be superparamagnetic and has saturation magnetization at 5 K but [2Fe–2S]-MagR is paramagnetic. While at 300 K, [2Fe–2S]-MagR is diamagnetic but [3Fe–4S]-MagR is paramagnetic. Together, the different types of iron–sulfur cluster binding in MagR attribute distinguished magnetic properties, which may provide a fascinating mechanism for animals to modulate the sensitivity in magnetic sensing.

scholarly journals A Role for Iron-Sulfur Clusters in the Regulation of Transcription Factor Yap5-dependent High Iron Transcriptional Responses in Yeast

2012 ◽  
Vol 287 (42) ◽  
pp. 35709-35721 ◽  
Author(s):  
Liangtao Li ◽  
Ren Miao ◽  
Sophie Bertram ◽  
Xuan Jia ◽  
Diane M. Ward ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Target Genes ◽  
Transcriptional Response ◽  
Regulation Of Transcription ◽  
Transcriptional Responses ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur Clusters ◽  
Sulfur Cluster ◽  
High Iron ◽  
Iron Sulfur

Yeast respond to increased cytosolic iron by activating the transcription factor Yap5 increasing transcription of CCC1, which encodes a vacuolar iron importer. Using a genetic screen to identify genes involved in Yap5 iron sensing, we discovered that a mutation in SSQ1, which encodes a mitochondrial chaperone involved in iron-sulfur cluster synthesis, prevented expression of Yap5 target genes. We demonstrated that mutation or reduced expression of other genes involved in mitochondrial iron-sulfur cluster synthesis (YFH1, ISU1) prevented induction of the Yap5 response. We took advantage of the iron-dependent catalytic activity of Pseudaminobacter salicylatoxidans gentisate 1,2-dioxygenase expressed in yeast to measure changes in cytosolic iron. We determined that reductions in iron-sulfur cluster synthesis did not affect the activity of cytosolic gentisate 1,2-dioxygenase. We show that loss of activity of the cytosolic iron-sulfur cluster assembly complex proteins or deletion of cytosolic glutaredoxins did not reduce expression of Yap5 target genes. These results suggest that the high iron transcriptional response, as well as the low iron transcriptional response, senses iron-sulfur clusters.

Research on isc Operon in Acidithiobacillus ferrooxidans ATCC 23270

2007 ◽  
Vol 20-21 ◽  
pp. 509-512 ◽  
Author(s):  
Jian She Liu ◽  
Yan Fei Zhang ◽  
Mei Mei Geng ◽  
Jia Zeng ◽  
Guan Zhou Qiu
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Purification And Characterization ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur Clusters ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Iron Sulfur Proteins

The highly conserved operon iron–sulfur cluster (iscSUA) is essential for the general biogenesis and transfer of iron–sulfur proteins in bacteria. In this study, expression, purification and characterization of the proteins of the isc operon (iscSUA) of Acidithiobacillus ferrooxidans ATCC 23270 was studied. Assembly and transfer of [Fe4S4] in vitro during the isc proteins and other iron sulfur proteins was studied in order to detect the pathway and mechanism of [Fe4S4] assembly and transfer in vivo. The [Fe4S4] cluster was successfully assembled in iron-sulfur proteins in vitro in the presence of Fe2+ and sulfide, and it was successfully transferred from IscA or IscU to iron- sulfur proteins. Our results support and extend certain models of iron-sulfur clusters assembly and transfer.

scholarly journals Bridging a gap in iron-sulfur cluster assembly

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Erin L. McCarthy ◽  
Squire J. Booker
Keyword(s):  
Adaptor Proteins ◽  
Cluster Assembly ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur Clusters ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Cellular Machinery

The cellular machinery that incorporates iron-sulfur clusters into proteins is directed to particular targets by adaptor proteins.

Complementary roles of SufA and IscA in the biogenesis of iron–sulfur clusters in Escherichia coli

2007 ◽  
Vol 409 (2) ◽  
pp. 535-543 ◽  
Author(s):  
Jianxin Lu ◽  
Juanjuan Yang ◽  
Guoqiang Tan ◽  
Huangen Ding
Keyword(s):  
Cell Growth ◽  
Double Mutant ◽  
Iron Binding ◽  
Cluster Assembly ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur Clusters ◽  
Sulfur Cluster ◽  
E Coli ◽  
Iron Sulfur ◽  
Iron Binding Protein

Biogenesis of iron–sulfur clusters requires a concerted delivery of iron and sulfur to target proteins. It is now clear that sulfur in iron–sulfur clusters is derived from L-cysteine via cysteine desulfurases. However, the specific iron donor for the iron–sulfur cluster assembly still remains elusive. Previous studies showed that IscA, a member of the iron–sulfur cluster assembly machinery in Escherichia coli, is a novel iron-binding protein, and that the iron-bound IscA can provide iron for the iron–sulfur cluster assembly in a proposed scaffold IscU in vitro. However, genetic studies have indicated that IscA is not essential for the cell growth of E. coli. In the present paper, we report that SufA, an IscA paralogue in E. coli, may represent the redundant activity of IscA. Although deletion of IscA or SufA has only a mild effect on cell growth, deletion of both IscA and SufA in E. coli results in a severe growth phenotype in minimal medium under aerobic growth conditions. Cell growth is restored when either IscA or SufA is re-introduced into the iscA−/sufA− double mutant, demonstrating further that either IscA or SufA is sufficient for their functions in vivo. Purified SufA, like IscA, is an iron-binding protein that can provide iron for the iron–sulfur cluster assembly in IscU in the presence of a thioredoxin reductase system which emulates the intracellular redox potential. Site-directed mutagenesis studies show that the SufA/IscA variants that lose the specific iron-binding activity fail to restore the cell growth of the iscA−/sufA− double mutant. The results suggest that SufA and IscA may constitute the redundant cellular activities to recruit intracellular iron and deliver iron for the iron–sulfur cluster assembly in E. coli.

scholarly journals Iron-sulfur clusters are involved in post-translational arginylation

2021 ◽  
Author(s):  
Verna Van ◽  
Janae B. Brown ◽  
Hannah Rosenbach ◽  
Ijaz Mohamed ◽  
Nna-Emeka Ejimogu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Molecular Mechanism ◽  
Half Life ◽  
Regulatory Control ◽  
Post Translational Modification ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur Clusters ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Oxygen Sensitive

Eukaryotic arginylation is an essential post-translational modification that both modulates protein stability and regulates protein half-life through the N-degron pathway. Arginylation is catalyzed by a family of enzymes known as the arginyl-tRNA transferases (ATE1s), which are conserved across the eukaryotic domain. Despite its conservation and importance, little is known regarding the structure, mechanism, and regulation of ATE1s. In this work, we have discovered that ATE1s bind a previously unknown iron-sulfur cluster that is conserved across evolution. We have extensively characterized the nature of this iron-sulfur cluster, and we show that the presence of the iron-sulfur cluster is linked to alterations in arginylation efficacy. Finally, we demonstrate that the ATE1 iron-sulfur cluster is oxygen sensitive, which could be a molecular mechanism of the N-degron pathway to sense oxidative stress. Thus, our data provide the framework of a cluster-based paradigm of ATE1 regulatory control.

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