scholarly journals The mitochondrial monothiol glutaredoxin S15 is essential for iron-sulfur protein maturation in Arabidopsis thaliana

2015 ◽  
Vol 112 (44) ◽  
pp. 13735-13740 ◽  
Author(s):  
Anna Moseler ◽  
Isabel Aller ◽  
Stephan Wagner ◽  
Thomas Nietzel ◽  
Jonathan Przybyla-Toscano ◽  
...  
Keyword(s):  
Amino Acid Residues ◽  
Iron Sulfur Cluster ◽  
Growth Defects ◽  
Iron Sulfur ◽  
Iron Sulfur Proteins ◽  
Dna Insertion ◽  
Sulfur Protein ◽  
Metabolic Reactions ◽  
Insertion Mutants

The iron-sulfur cluster (ISC) is an ancient and essential cofactor of many proteins involved in electron transfer and metabolic reactions. In Arabidopsis, three pathways exist for the maturation of iron-sulfur proteins in the cytosol, plastids, and mitochondria. We functionally characterized the role of mitochondrial glutaredoxin S15 (GRXS15) in biogenesis of ISC containing aconitase through a combination of genetic, physiological, and biochemical approaches. Two Arabidopsis T-DNA insertion mutants were identified as null mutants with early embryonic lethal phenotypes that could be rescued by GRXS15. Furthermore, we showed that recombinant GRXS15 is able to coordinate and transfer an ISC and that this coordination depends on reduced glutathione (GSH). We found the Arabidopsis GRXS15 able to complement growth defects based on disturbed ISC protein assembly of a yeast Δgrx5 mutant. Modeling of GRXS15 onto the crystal structures of related nonplant proteins highlighted amino acid residues that after mutation diminished GSH and subsequently ISC coordination, as well as the ability to rescue the yeast mutant. When used for plant complementation, one of these mutant variants, GRXS15K83/A, led to severe developmental delay and a pronounced decrease in aconitase activity by approximately 65%. These results indicate that mitochondrial GRXS15 is an essential protein in Arabidopsis, required for full activity of iron-sulfur proteins.

scholarly journals Understanding the role of dynamics in the iron sulfur cluster molecular machine

2017 ◽  
Vol 1861 (1) ◽  
pp. 3154-3163 ◽  
Author(s):  
Danilo di Maio ◽  
Balasubramanian Chandramouli ◽  
Robert Yan ◽  
Giuseppe Brancato ◽  
Annalisa Pastore
Keyword(s):  
Molecular Machine ◽  
Iron Sulfur Cluster ◽  
Sulfur Cluster ◽  
Iron Sulfur

scholarly journals IBA57 mutations abrogate iron-sulfur cluster assembly leading to cavitating leukoencephalopathy

2017 ◽  
Vol 3 (5) ◽  
pp. e184 ◽  
Author(s):  
Akihiko Ishiyama ◽  
Chika Sakai ◽  
Yuichi Matsushima ◽  
Satoru Noguchi ◽  
Satomi Mitsuhashi ◽  
...  
Keyword(s):  
Protein Expression ◽  
Lipoic Acid ◽  
Protein Assembly ◽  
Assembly System ◽  
Iron Sulfur Cluster ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Mitochondrial Iron ◽  
Sulfur Protein ◽  
Iron Sulfur Protein

Objective:To determine the molecular factors contributing to progressive cavitating leukoencephalopathy (PCL) to help resolve the underlying genotype-phenotype associations in the mitochondrial iron-sulfur cluster (ISC) assembly system.Methods:The subjects were 3 patients from 2 families who showed no inconsistencies in either clinical or brain MRI findings as PCL. We used exome sequencing, immunoblotting, and enzyme activity assays to establish a molecular diagnosis and determine the roles of ISC-associated factors in PCL.Results:We performed genetic analyses on these 3 patients and identified compound heterozygosity for the IBA57 gene, which encodes the mitochondrial iron-sulfur protein assembly factor. Protein expression analysis revealed substantial decreases in IBA57 protein expression in myoblasts and fibroblasts. Immunoblotting revealed substantially reduced expression of SDHB, a subunit of complex II, and lipoic acid synthetase (LIAS). Levels of pyruvate dehydrogenase complex-E2 and α-ketoglutarate dehydrogenase-E2, which use lipoic acid as a cofactor, were also reduced. In activity staining, SDH activity was clearly reduced, but it was ameliorated in mitochondrial fractions from rescued myoblasts. In addition, NFU1 protein expression was also decreased, which is required for the assembly of a subset of iron-sulfur proteins to SDH and LIAS in the mitochondrial ISC assembly system.Conclusions:Defects in IBA57 essentially regulate NFU1 expression, and aberrant NFU1 ultimately affects SDH activity and LIAS expression in the ISC biogenesis pathway. This study provides new insights into the role of the iron-sulfur protein assembly system in disorders related to mitochondrial energy metabolism associated with leukoencephalopathy with cavities.

The HiPIP from the acidophilic Acidithiobacillus ferrooxidans is correctly processed and translocated in Escherichia coli, in spite of the periplasm pH difference between these two micro-organisms

Microbiology ◽  
2005 ◽  
Vol 151 (5) ◽  
pp. 1421-1431 ◽  
Author(s):  
Patrice Bruscella ◽  
Laure Cassagnaud ◽  
Jeanine Ratouchniak ◽  
Gaël Brasseur ◽  
Elisabeth Lojou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acidithiobacillus Ferrooxidans ◽  
Biochemical Properties ◽  
Gene Encoding ◽  
Iron Sulfur Cluster ◽  
E Coli ◽  
Iron Sulfur ◽  
Sulfur Protein ◽  
Tat System ◽  
Micro Organisms

The gene encoding a putative high-potential iron–sulfur protein (HiPIP) from the strictly acidophilic and chemolithoautotrophic Acidithiobacillus ferrooxidans ATCC 33020 has been cloned and sequenced. This potential HiPIP was overproduced in the periplasm of the neutrophile and heterotroph Escherichia coli. As shown by optical and EPR spectra and by electrochemical studies, the recombinant protein has all the biochemical properties of a HiPIP, indicating that the iron–sulfur cluster was correctly inserted. Translocation of this protein in the periplasm of E. coli was not detected in a ΔtatC mutant, indicating that it is dependent on the Tat system. The genetic organization of the iro locus in strains ATCC 23270 and ATCC 33020 is different from that found in strains Fe-1 and BRGM. Indeed, in A. ferrooxidans ATCC 33020 and ATCC 23270 (the type strain), iro was not located downstream from purA but was instead downstream from petC2, encoding cytochrome c 1 from the second A. ferrooxidans cytochrome bc 1 complex. These findings underline the genotypic heterogeneity within the A. ferrooxidans species. The results suggest that Iro transfers electrons from a cytochrome bc 1 complex to a terminal oxidase, as proposed for the HiPIP in photosynthetic bacteria.

Dependence of heme biosynthesis on iron-sulfur cluster biogenesis: human ALAD is an unrecognized iron-sulfur protein

2020 ◽  
Author(s):  
Gang Liu ◽  
Debangsu Sil ◽  
Wing-Hang Tong ◽  
Nunziata Maio ◽  
J. Martin Bollinger ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Biosynthetic Pathway ◽  
Aminolevulinic Acid ◽  
Heme Biosynthesis ◽  
Second Step ◽  
Iron Sulfur Cluster ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Sulfur Protein ◽  
Iron Sulfur Protein

Abstract Heme biosynthesis and iron-sulfur cluster (ISC) biogenesis are two major mammalian metabolic pathways that require iron. It has long been known that these two pathways interconnect, but the previously described interactions do not fully explain why heme biosynthesis depends on intact ISC biogenesis. Herein we have identified a previously unrecognized connection between these two pathways through our discovery that human aminolevulinic acid dehydratase (ALAD), which catalyzes the second step of heme biosynthesis, is an Fe-S protein. We found that several highly conserved cysteines and an Ala306-Phe307-Arg308 motif of human ALAD are important for [Fe4S4] cluster acquisition and coordination. The enzymatic activity of human ALAD was greatly reduced upon loss of its Fe-S cluster, which resulted in reduced heme biosynthesis in human cells. Our findings explain why heme biosynthesis depends on intact ISC biogenesis, as ALAD provides an early Fe-S-dependent checkpoint in the heme biosynthetic pathway.

scholarly journals A Model of Aerobic and Anaerobic Metabolism of Hydrogen in the Extremophile Acidithiobacillus ferrooxidans

2020 ◽  
Vol 11 ◽  
Author(s):  
Jiri Kucera ◽  
Jan Lochman ◽  
Pavel Bouchal ◽  
Eva Pakostova ◽  
Kamil Mikulasek ◽  
...  
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Hydrogen Oxidation ◽  
Current Knowledge ◽  
Proton Efflux ◽  
Iron Sulfur ◽  
Sulfur Protein ◽  
Iron Sulfur Protein ◽  
Terrestrial Subsurface ◽  
Aerobic And Anaerobic

Hydrogen can serve as an electron donor for chemolithotrophic acidophiles, especially in the deep terrestrial subsurface and geothermal ecosystems. Nevertheless, the current knowledge of hydrogen utilization by mesophilic acidophiles is minimal. A multi-omics analysis was applied on Acidithiobacillus ferrooxidans growing on hydrogen, and a respiratory model was proposed. In the model, [NiFe] hydrogenases oxidize hydrogen to two protons and two electrons. The electrons are used to reduce membrane-soluble ubiquinone to ubiquinol. Genetically associated iron-sulfur proteins mediate electron relay from the hydrogenases to the ubiquinone pool. Under aerobic conditions, reduced ubiquinol transfers electrons to either cytochrome aa3 oxidase via cytochrome bc1 complex and cytochrome c4 or the alternate directly to cytochrome bd oxidase, resulting in proton efflux and reduction of oxygen. Under anaerobic conditions, reduced ubiquinol transfers electrons to outer membrane cytochrome c (ferrireductase) via cytochrome bc1 complex and a cascade of electron transporters (cytochrome c4, cytochrome c552, rusticyanin, and high potential iron-sulfur protein), resulting in proton efflux and reduction of ferric iron. The proton gradient generated by hydrogen oxidation maintains the membrane potential and allows the generation of ATP and NADH. These results further clarify the role of extremophiles in biogeochemical processes and their impact on the composition of the deep terrestrial subsurface.

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