scholarly journals Construction of Synthetic Models for Nitrogenase-Relevant NifB Biogenesis Intermediates and Iron-Carbide-Sulfide Clusters

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1317
Author(s):  
Chris Joseph ◽  
John Patrick Shupp ◽  
Caitlyn R. Cobb ◽  
Michael J. Rose
Keyword(s):  
Iron Carbide ◽  
Research Groups ◽  
Iron Sulfur Clusters ◽  
Iron Sulfur ◽  
The Family ◽  
Primary Obstacle ◽  
Carbide Cluster ◽  
Sulfide Clusters ◽  
Synthetic Models ◽  
Critical Interest

The family of nitrogenase enzymes catalyzes the reduction of atmospheric dinitrogen (N2) to ammonia under remarkably benign conditions of temperature, pressure, and pH. Therefore, the development of synthetic complexes or materials that can similarly perform this reaction is of critical interest. The primary obstacle for obtaining realistic synthetic models of the active site iron-sulfur-carbide cluster (e.g., FeMoco) is the incorporation of a truly inorganic carbide. This review summarizes the present state of knowledge regarding biological and chemical (synthetic) incorporation of carbide into iron-sulfur clusters. This includes the Nif cluster of proteins and associated biochemistry involved in the endogenous biogenesis of FeMoco. We focus on the chemical (synthetic) incorporation portion of our own efforts to incorporate and modify C1 units in iron/sulfur clusters. We also highlight recent contributions from other research groups in the area toward C1 and/or inorganic carbide insertion.

scholarly journals Synthetic Models for Nickel–Iron Hydrogenase Featuring Redox-Active Ligands

2017 ◽  
Vol 70 (5) ◽  
pp. 505 ◽  
Author(s):  
David Schilter ◽  
Danielle L. Gray ◽  
Amy L. Fuller ◽  
Thomas B. Rauchfuss
Keyword(s):  
Active Sites ◽  
Iron Sulfur Clusters ◽  
Nickel Iron Hydrogenase ◽  
Nickel Iron ◽  
Redox States ◽  
Iron Sulfur ◽  
Proton Relay ◽  
Redox Active ◽  
Iron Hydrogenase ◽  
Synthetic Models

The nickel–iron hydrogenase enzymes efficiently and reversibly interconvert protons, electrons, and dihydrogen. These redox proteins feature iron–sulfur clusters that relay electrons to and from their active sites. Reported here are synthetic models for nickel–iron hydrogenase featuring redox-active auxiliaries that mimic the iron–sulfur cofactors. The complexes prepared are NiII(μ-H)FeIIFeII species of formula [(diphosphine)Ni(dithiolate)(μ-H)Fe(CO)2(ferrocenylphosphine)]+ or NiIIFeIFeII complexes [(diphosphine)Ni(dithiolate)Fe(CO)2(ferrocenylphosphine)]+ (diphosphine = Ph2P(CH2)2PPh2 or Cy2P(CH2)2PCy2; dithiolate = –S(CH2)3S–; ferrocenylphosphine = diphenylphosphinoferrocene, diphenylphosphinomethyl(nonamethylferrocene) or 1,1′-bis(diphenylphosphino)ferrocene). The hydride species is a catalyst for hydrogen evolution, while the latter hydride-free complexes can exist in four redox states – a feature made possible by the incorporation of the ferrocenyl groups. Mixed-valent complexes of 1,1′-bis(diphenylphosphino)ferrocene have one of the phosphine groups unbound, with these species representing advanced structural models with both a redox-active moiety (the ferrocene group) and a potential proton relay (the free phosphine) proximal to a nickel–iron dithiolate.

scholarly journals Fe-S cofactors in the SARS-CoV-2 RNA-dependent RNA polymerase are potential antiviral targets

Science ◽  
2021 ◽  
pp. eabi5224
Author(s):  
Nunziata Maio ◽  
Bernard A. P. Lafont ◽  
Debangsu Sil ◽  
Yan Li ◽  
J. Martin Bollinger ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Metal Binding ◽  
Rna Dependent Rna Polymerase ◽  
Iron Sulfur Clusters ◽  
Metal Binding Sites ◽  
Iron Sulfur ◽  
Cryo Electron Microscopy ◽  
Metal Cofactors ◽  
Antiviral Targets ◽  
Viral Helicase

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of coronavirus disease 2019 (COVID-19), uses an RNA-dependent RNA polymerase (RdRp) for the replication of its genome and the transcription of its genes. We found that the catalytic subunit of the RdRp, nsp12, ligates two iron-sulfur metal cofactors in sites that were modeled as zinc centers in the available cryo-electron microscopy structures of the RdRp complex. These metal binding sites are essential for replication and for interaction with the viral helicase. Oxidation of the clusters by the stable nitroxide TEMPOL caused their disassembly, potently inhibited the RdRp, and blocked SARS-CoV-2 replication in cell culture. These iron-sulfur clusters thus serve as cofactors for the SARS-CoV-2 RdRp and are targets for therapy of COVID-19.

EPR-derived structures of flavin radical and iron-sulfur clusters from Methylosinus sporium 5 reductase

2021 ◽  
Author(s):  
Han Sol Jeong ◽  
Sugyeong Hong ◽  
Hee Seon Yoo ◽  
Jin Kim ◽  
Yujeong Kim ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Crucial Role ◽  
Methane Monooxygenase ◽  
Global Carbon Cycle ◽  
Ambient Conditions ◽  
Iron Sulfur Clusters ◽  
Iron Sulfur ◽  
Greenhouse Effects ◽  
Global Carbon ◽  
Significant Attention

Methane monooxygenase (MMO) has attracted significant attention owing to its crucial role in the global carbon cycle; it impedes greenhouse effects by converting methane to methanol under ambient conditions. The...

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.

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