scholarly journals N-terminal tyrosine of ISCU2 triggers [2Fe-2S] cluster synthesis by ISCU2 dimerization

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sven-A. Freibert ◽  
Michal T. Boniecki ◽  
Claudia Stümpfig ◽  
Vinzent Schulz ◽  
Nils Krapoth ◽  
...  
Keyword(s):  
De Novo ◽  
Cluster Formation ◽  
Cluster Assembly ◽  
Cysteine Desulfurase ◽  
Iron Sulfur Cluster ◽  
Mutant Proteins ◽  
Iron Sulfur ◽  
Initial Iron ◽  
Oppositely Charged

AbstractSynthesis of iron-sulfur (Fe/S) clusters in living cells requires scaffold proteins for both facile synthesis and subsequent transfer of clusters to target apoproteins. The human mitochondrial ISCU2 scaffold protein is part of the core ISC (iron-sulfur cluster assembly) complex that synthesizes a bridging [2Fe-2S] cluster on dimeric ISCU2. Initial iron and sulfur loading onto monomeric ISCU2 have been elucidated biochemically, yet subsequent [2Fe-2S] cluster formation and dimerization of ISCU2 is mechanistically ill-defined. Our structural, biochemical and cell biological experiments now identify a crucial function of the universally conserved N-terminal Tyr35 of ISCU2 for these late reactions. Mixing two, per se non-functional ISCU2 mutant proteins with oppositely charged Asp35 and Lys35 residues, both bound to different cysteine desulfurase complexes NFS1-ISD11-ACP, restores wild-type ISCU2 maturation demonstrating that ionic forces can replace native Tyr-Tyr interactions during dimerization-induced [2Fe-2S] cluster formation. Our studies define the essential mechanistic role of Tyr35 in the reaction cycle of de novo mitochondrial [2Fe-2S] cluster synthesis.

scholarly journals Role of Saccharomyces cerevisiae ISA1and ISA2 in Iron Homeostasis

2000 ◽  
Vol 20 (11) ◽  
pp. 3918-3927 ◽  
Author(s):  
Laran T. Jensen ◽  
Valeria Cizewski Culotta
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Iron Homeostasis ◽  
Cluster Formation ◽  
Iron Concentration ◽  
Intermembrane Space ◽  
Cluster Assembly ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur ◽  
Yeast Genes

ABSTRACT The budding yeast Saccharomyces cerevisiae contains two homologues of bacterial IscA proteins, designated Isa1p and Isa2p. Bacterial IscA is a product of the isc (iron-sulfur cluster) operon and has been suggested to participate in Fe-S cluster formation or repair. To test the function of yeast Isa1p and Isa2p, single or combinatorial disruptions were introduced in ISA1and ISA2. The resultant isaΔ mutants were viable but exhibited a dependency on lysine and glutamate for growth and a respiratory deficiency due to an accumulation of mutations in mitochondrial DNA. As with other yeast genes proposed to function in Fe-S cluster assembly, mitochondrial iron concentration was significantly elevated in the isa mutants, and the activities of the Fe-S cluster-containing enzymes aconitase and succinate dehydrogenase were dramatically reduced. An inspection of Isa-like proteins from bacteria to mammals revealed three invariant cysteine residues, which in the case of Isa1p and Isa2p are essential for function and may be involved in iron binding. As predicted, Isa1p is targeted to the mitochondrial matrix. However, Isa2p is present within the intermembrane space of the mitochondria. Our deletion analyses revealed that Isa2p harbors a bipartite N-terminal leader sequence containing a mitochondrial import signal linked to a second sequence that targets Isa2p to the intermembrane space. Both signals are needed for Isa2p function. A model for the nonredundant roles of Isa1p and Isa2p in delivering iron to sites of the Fe-S cluster assembly is discussed.

scholarly journals Sulfur Administration in Fe–S Cluster Homeostasis

Antioxidants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1738
Author(s):  
Leszek Rydz ◽  
Maria Wróbel ◽  
Halina Jurkowska
Keyword(s):  
Oxidative Stress ◽  
Cluster Formation ◽  
Electron Donors ◽  
Cluster Assembly ◽  
Cysteine Desulfurase ◽  
Iron Sulfur Cluster ◽  
Sulfur Transfer ◽  
Iron Sulfur ◽  
Mercaptopyruvate Sulfurtransferase ◽  
Nuclear Cluster

Mitochondria are the key organelles of Fe–S cluster synthesis. They contain the enzyme cysteine desulfurase, a scaffold protein, iron and electron donors, and specific chaperons all required for the formation of Fe–S clusters. The newly formed cluster can be utilized by mitochondrial Fe–S protein synthesis or undergo further transformation. Mitochondrial Fe–S cluster biogenesis components are required in the cytosolic iron–sulfur cluster assembly machinery for cytosolic and nuclear cluster supplies. Clusters that are the key components of Fe–S proteins are vulnerable and prone to degradation whenever exposed to oxidative stress. However, once degraded, the Fe–S cluster can be resynthesized or repaired. It has been proposed that sulfurtransferases, rhodanese, and 3-mercaptopyruvate sulfurtransferase, responsible for sulfur transfer from donor to nucleophilic acceptor, are involved in the Fe–S cluster formation, maturation, or reconstitution. In the present paper, we attempt to sum up our knowledge on the involvement of sulfurtransferases not only in sulfur administration but also in the Fe–S cluster formation in mammals and yeasts, and on reconstitution-damaged cluster or restoration of enzyme’s attenuated activity.

scholarly journals Mechanism of Iron–Sulfur Cluster Assembly: In the Intimacy of Iron and Sulfur Encounter

Inorganics ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 55
Author(s):  
Batoul Srour ◽  
Sylvain Gervason ◽  
Beata Monfort ◽  
Benoit D’Autréaux
Keyword(s):  
Cluster Assembly ◽  
Cysteine Desulfurase ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur ◽  
Physiological Relevance ◽  
Client Proteins ◽  
Sulfide Ions ◽  
Cluster Biosynthesis

Iron–sulfur (Fe–S) clusters are protein cofactors of a multitude of enzymes performing essential biological functions. Specialized multi-protein machineries present in all types of organisms support their biosynthesis. These machineries encompass a scaffold protein on which Fe–S clusters are assembled and a cysteine desulfurase that provides sulfur in the form of a persulfide. The sulfide ions are produced by reductive cleavage of the persulfide, which involves specific reductase systems. Several other components are required for Fe–S biosynthesis, including frataxin, a key protein of controversial function and accessory components for insertion of Fe–S clusters in client proteins. Fe–S cluster biosynthesis is thought to rely on concerted and carefully orchestrated processes. However, the elucidation of the mechanisms of their assembly has remained a challenging task due to the biochemical versatility of iron and sulfur and the relative instability of Fe–S clusters. Nonetheless, significant progresses have been achieved in the past years, using biochemical, spectroscopic and structural approaches with reconstituted system in vitro. In this paper, we review the most recent advances on the mechanism of assembly for the founding member of the Fe–S cluster family, the [2Fe2S] cluster that is the building block of all other Fe–S clusters. The aim is to provide a survey of the mechanisms of iron and sulfur insertion in the scaffold proteins by examining how these processes are coordinated, how sulfide is produced and how the dinuclear [2Fe2S] cluster is formed, keeping in mind the question of the physiological relevance of the reconstituted systems. We also cover the latest outcomes on the functional role of the controversial frataxin protein in Fe–S cluster biosynthesis.

scholarly journals Iron–sulfur cluster biosynthesis

2008 ◽  
Vol 36 (6) ◽  
pp. 1112-1119 ◽  
Author(s):  
Sibali Bandyopadhyay ◽  
Kala Chandramouli ◽  
Michael K. Johnson
Keyword(s):  
Scaffold Proteins ◽  
Cluster Assembly ◽  
Cysteine Desulfurase ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur ◽  
Eukaryotic Organisms ◽  
Almost All ◽  
Cluster Biosynthesis

Iron–sulfur (Fe–S) clusters are present in more than 200 different types of enzymes or proteins and constitute one of the most ancient, ubiquitous and structurally diverse classes of biological prosthetic groups. Hence the process of Fe–S cluster biosynthesis is essential to almost all forms of life and is remarkably conserved in prokaryotic and eukaryotic organisms. Three distinct types of Fe–S cluster assembly machinery have been established in bacteria, termed the NIF, ISC and SUF systems, and, in each case, the overall mechanism involves cysteine desulfurase-mediated assembly of transient clusters on scaffold proteins and subsequent transfer of pre-formed clusters to apo proteins. A molecular level understanding of the complex processes of Fe–S cluster assembly and transfer is now beginning to emerge from the combination of in vivo and in vitro approaches. The present review highlights recent developments in understanding the mechanism of Fe–S cluster assembly and transfer involving the ubiquitous U-type scaffold proteins and the potential roles of accessory proteins such as Nfu proteins and monothiol glutaredoxins in the assembly, storage or transfer of Fe–S clusters.

scholarly journals The Role of CyaY in Iron Sulfur Cluster Assembly on the E. coli IscU Scaffold Protein

PLoS ONE ◽  
2011 ◽  
Vol 6 (7) ◽  
pp. e21992 ◽  
Author(s):  
Clara Iannuzzi ◽  
Salvatore Adinolfi ◽  
Barry D. Howes ◽  
Ricardo Garcia-Serres ◽  
Martin Clémancey ◽  
...  
Keyword(s):  
Scaffold Protein ◽  
Cluster Assembly ◽  
Iron Sulfur Cluster ◽  
Sulfur Cluster ◽  
E Coli ◽  
Iron Sulfur

Mechanisms of Mitochondrial Iron-Sulfur Protein Biogenesis

2020 ◽  
Vol 89 (1) ◽  
pp. 471-499 ◽  
Author(s):  
Roland Lill ◽  
Sven-A. Freibert
Keyword(s):  
Molecular Mechanisms ◽  
De Novo ◽  
Lipid Synthesis ◽  
Cluster Assembly ◽  
Iron Sulfur Cluster ◽  
Atp Production ◽  
Cellular Iron ◽  
Iron Sulfur ◽  
Sulfur Protein ◽  
S Proteins

Mitochondria are essential in most eukaryotes and are involved in numerous biological functions including ATP production, cofactor biosyntheses, apoptosis, lipid synthesis, and steroid metabolism. Work over the past two decades has uncovered the biogenesis of cellular iron-sulfur (Fe/S) proteins as the essential and minimal function of mitochondria. This process is catalyzed by the bacteria-derived iron-sulfur cluster assembly (ISC) machinery and has been dissected into three major steps: de novo synthesis of a [2Fe-2S] cluster on a scaffold protein; Hsp70 chaperone–mediated trafficking of the cluster and insertion into [2Fe-2S] target apoproteins; and catalytic conversion of the [2Fe-2S] into a [4Fe-4S] cluster and subsequent insertion into recipient apoproteins. ISC components of the first two steps are also required for biogenesis of numerous essential cytosolic and nuclear Fe/S proteins, explaining the essentiality of mitochondria. This review summarizes the molecular mechanisms underlying the ISC protein–mediated maturation of mitochondrial Fe/S proteins and the importance for human disease.

scholarly journals Identification of IscU residues critical for de novo iron–sulfur cluster assembly

2019 ◽  
Vol 112 (6) ◽  
pp. 1769-1783
Author(s):  
Naoyuki Tanaka ◽  
Eiki Yuda ◽  
Takashi Fujishiro ◽  
Kei Hirabayashi ◽  
Kei Wada ◽  
...  
Keyword(s):  
De Novo ◽  
Cluster Assembly ◽  
Iron Sulfur Cluster ◽  
Sulfur Cluster ◽  
Iron Sulfur
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