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.

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.

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 Dimers of glutaredoxin 2 as mitochondrial redox sensors in selenite-induced oxidative stress

Metallomics ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1241-1251 ◽  
Author(s):  
Valeria Scalcon ◽  
Federica Tonolo ◽  
Alessandra Folda ◽  
Alberto Bindoli ◽  
Maria Pia Rigobello
Keyword(s):  
Oxidative Stress ◽  
Iron Release ◽  
Iron Sulfur Cluster ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Redox Sensors

Grx2 coordinates an iron–sulfur cluster, forming inactive dimers. In mitochondria, Grx2 monomerization, after oxidative stress, determines iron release triggering apoptosis.

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