scholarly journals The auxiliary [4Fe–4S] cluster of the Radical SAM heme synthase from Methanosarcina barkeri is involved in electron transfer

2016 ◽  
Vol 7 (7) ◽  
pp. 4633-4643 ◽  
Author(s):  
Melanie Kühner ◽  
Peter Schweyen ◽  
Martin Hoffmann ◽  
José Vazquez Ramos ◽  
Edward J. Reijerse ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Methanosarcina Barkeri ◽  
Heme Biosynthesis ◽  
Oxidative Decarboxylation ◽  
Side Chains ◽  
Biosynthesis Pathway ◽  
Radical Sam

The heme synthase AhbD catalyzes the oxidative decarboxylation of two propionate side chains of iron-coproporphyrin III to the corresponding vinyl groups of heme during the alternative heme biosynthesis pathway.

scholarly journals The oxygen-independent coproporphyrinogen III oxidase HemN utilizes harderoporphyrinogen as a reaction intermediate during conversion of coproporphyrinogen III to protoporphyrinogen IX

2010 ◽  
Vol 391 (1) ◽  
Author(s):  
Katrin Rand ◽  
Claudia Noll ◽  
Hans Martin Schiebel ◽  
Dorit Kemken ◽  
Thomas Dülcks ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Hplc Analysis ◽  
Heme Biosynthesis ◽  
Chromatographic Behavior ◽  
Side Chain ◽  
Oxidative Decarboxylation ◽  
Side Chains ◽  
Reaction Intermediate ◽  
Coproporphyrinogen Iii Oxidase

Abstract During heme biosynthesis the oxygen-independent coproporphyrinogen III oxidase HemN catalyzes the oxidative decarboxylation of the two propionate side chains on rings A and B of coproporphyrinogen III to the corresponding vinyl groups to yield protoporphyrinogen IX. Here, the sequence of the two decarboxylation steps during HemN catalysis was investigated. A reaction intermediate of HemN activity was isolated by HPLC analysis and identified as monovinyltripropionic acid porphyrin by mass spectrometry. This monovinylic reaction intermediate exhibited identical chromatographic behavior during HPLC analysis as harderoporphyrin (3-vinyl-8,13,17-tripropionic acid-2,7,12,18-tetramethylporphyrin). Furthermore, HemN was able to utilize chemically synthesized harderoporphyrinogen as substrate and converted it to protoporphyrinogen IX. These results suggest that during HemN catalysis the propionate side chain of ring A of coproporphyrinogen III is decarboxylated prior to that of ring B.

scholarly journals Direct Interspecies Electron Transfer between Geobacter metallireducens and Methanosarcina barkeri

2014 ◽  
Vol 80 (15) ◽  
pp. 4599-4605 ◽  
Author(s):  
Amelia-Elena Rotaru ◽  
Pravin Malla Shrestha ◽  
Fanghua Liu ◽  
Beatrice Markovaite ◽  
Shanshan Chen ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Model Organism ◽  
Methanosarcina Barkeri ◽  
Physical Contact ◽  
Acetate Metabolism ◽  
Geobacter Metallireducens ◽  
Content Type ◽  
Direct Interspecies Electron Transfer ◽  
Interspecies Electron Transfer ◽  
Effective Form

ABSTRACTDirect interspecies electron transfer (DIET) is potentially an effective form of syntrophy in methanogenic communities, but little is known about the diversity of methanogens capable of DIET. The ability ofMethanosarcina barkerito participate in DIET was evaluated in coculture withGeobacter metallireducens. Cocultures formed aggregates that shared electrons via DIET during the stoichiometric conversion of ethanol to methane. Cocultures could not be initiated with a pilin-deficientG. metallireducensstrain, suggesting that long-range electron transfer along pili was important for DIET. Amendments of granular activated carbon permitted the pilin-deficientG. metallireducensisolates to share electrons withM. barkeri, demonstrating that this conductive material could substitute for pili in promoting DIET. WhenM. barkeriwas grown in coculture with the H2-producingPelobacter carbinolicus, incapable of DIET,M. barkeriutilized H2as an electron donor but metabolized little of the acetate thatP. carbinolicusproduced. This suggested that H2, but not electrons derived from DIET, inhibited acetate metabolism.P. carbinolicus-M. barkericocultures did not aggregate, demonstrating that, unlike DIET, close physical contact was not necessary for interspecies H2transfer.M. barkeriis the second methanogen found to accept electrons via DIET and the first methanogen known to be capable of using either H2or electrons derived from DIET for CO2reduction. Furthermore,M. barkeriis genetically tractable, making it a model organism for elucidating mechanisms by which methanogens make biological electrical connections with other cells.

scholarly journals NFE2 regulates transcription of multiple enzymes in the heme biosynthesis pathway

Haematologica ◽  
2014 ◽  
Vol 99 (10) ◽  
pp. e208-e210 ◽  
Author(s):  
L. Rheinemann ◽  
T. S. Seeger ◽  
J. Wehrle ◽  
H. L. Pahl
Keyword(s):  
Heme Biosynthesis ◽  
Biosynthesis Pathway

scholarly journals Laboratory Diagnosis of Porphyria

Diagnostics ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1343
Author(s):  
Elena Di Pierro ◽  
Michele De Canio ◽  
Rosa Mercadante ◽  
Maria Savino ◽  
Francesca Granata ◽  
...  
Keyword(s):  
Molecular Analysis ◽  
Diagnostic Testing ◽  
Laboratory Diagnosis ◽  
Clinical Suspicion ◽  
Enzymatic Activities ◽  
Heme Biosynthesis ◽  
Present Review ◽  
Biosynthesis Pathway ◽  
Clinical Presentations

Porphyrias are a group of diseases that are clinically and genetically heterogeneous and originate mostly from inherited dysfunctions of specific enzymes involved in heme biosynthesis. Such dysfunctions result in the excessive production and excretion of the intermediates of the heme biosynthesis pathway in the blood, urine, or feces, and these intermediates are responsible for specific clinical presentations. Porphyrias continue to be underdiagnosed, although laboratory diagnosis based on the measurement of metabolites could be utilized to support clinical suspicion in all symptomatic patients. Moreover, the measurement of enzymatic activities along with a molecular analysis may confirm the diagnosis and are, therefore, crucial for identifying pre-symptomatic carriers. The present review provides an overview of the laboratory assays used most commonly for establishing the diagnosis of porphyria. This would assist the clinicians in prescribing appropriate diagnostic testing and interpreting the testing results.

scholarly journals Putative Extracellular Electron Transfer in Methanogenic Archaea

2021 ◽  
Vol 12 ◽  
Author(s):  
Kailin Gao ◽  
Yahai Lu
Keyword(s):  
Electron Transfer ◽  
Methanogenic Archaea ◽  
Methanosarcina Barkeri ◽  
Extracellular Electron Transfer ◽  
Future Research ◽  
Methanosarcina Acetivorans ◽  
Geobacter Metallireducens ◽  
Methanosarcina Mazei ◽  
Current State ◽  
Electron Transfers

It has been suggested that a few methanogens are capable of extracellular electron transfers. For instance, Methanosarcina barkeri can directly capture electrons from the coexisting microbial cells of other species. Methanothrix harundinacea and Methanosarcina horonobensis retrieve electrons from Geobacter metallireducens via direct interspecies electron transfer (DIET). Recently, Methanobacterium, designated strain YSL, has been found to grow via DIET in the co-culture with Geobacter metallireducens. Methanosarcina acetivorans can perform anaerobic methane oxidation and respiratory growth relying on Fe(III) reduction through the extracellular electron transfer. Methanosarcina mazei is capable of electromethanogenesis under the conditions where electron-transfer mediators like H2 or formate are limited. The membrane-bound multiheme c-type cytochromes (MHC) and electrically-conductive cellular appendages have been assumed to mediate the extracellular electron transfer in bacteria like Geobacter and Shewanella species. These molecules or structures are rare but have been recently identified in a few methanogens. Here, we review the current state of knowledge for the putative extracellular electron transfers in methanogens and highlight the opportunities and challenges for future research.

scholarly journals Toxoplasma gondii requires its plant-like heme biosynthesis pathway for infection

2020 ◽  
Vol 16 (5) ◽  
pp. e1008499
Author(s):  
Amy Bergmann ◽  
Katherine Floyd ◽  
Melanie Key ◽  
Carly Dameron ◽  
Kerrick C. Rees ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Heme Biosynthesis ◽  
Biosynthesis Pathway

scholarly journals The Requirement of Inorganic Fe-S Clusters for the Biosynthesis of the Organometallic Molybdenum Cofactor

Inorganics ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 43
Author(s):  
Ralf R. Mendel ◽  
Thomas W. Hercher ◽  
Arkadiusz Zupok ◽  
Muhammad A. Hasnat ◽  
Silke Leimkühler
Keyword(s):  
Electron Transfer ◽  
Scaffold Protein ◽  
Molybdenum Cofactor ◽  
Cluster Assembly ◽  
Biosynthesis Pathway ◽  
Carrier Proteins ◽  
Essential Protein ◽  
Iron Sulfur ◽  
Prosthetic Groups

Iron-sulfur (Fe-S) clusters are essential protein cofactors. In enzymes, they are present either in the rhombic [2Fe-2S] or the cubic [4Fe-4S] form, where they are involved in catalysis and electron transfer and in the biosynthesis of metal-containing prosthetic groups like the molybdenum cofactor (Moco). Here, we give an overview of the assembly of Fe-S clusters in bacteria and humans and present their connection to the Moco biosynthesis pathway. In all organisms, Fe-S cluster assembly starts with the abstraction of sulfur from l-cysteine and its transfer to a scaffold protein. After formation, Fe-S clusters are transferred to carrier proteins that insert them into recipient apo-proteins. In eukaryotes like humans and plants, Fe-S cluster assembly takes place both in mitochondria and in the cytosol. Both Moco biosynthesis and Fe-S cluster assembly are highly conserved among all kingdoms of life. Moco is a tricyclic pterin compound with molybdenum coordinated through its unique dithiolene group. Moco biosynthesis begins in the mitochondria in a Fe-S cluster dependent step involving radical/S-adenosylmethionine (SAM) chemistry. An intermediate is transferred to the cytosol where the dithiolene group is formed, to which molybdenum is finally added. Further connections between Fe-S cluster assembly and Moco biosynthesis are discussed in detail.

scholarly journals The essential role of the transporter ABCG2 in the pathophysiology of erythropoietic protoporphyria

2019 ◽  
Vol 5 (9) ◽  
pp. eaaw6127 ◽  
Author(s):  
Pengcheng Wang ◽  
Madhav Sachar ◽  
Jie Lu ◽  
Amina I. Shehu ◽  
Junjie Zhu ◽  
...  
Keyword(s):  
Essential Role ◽  
Protoporphyrin Ix ◽  
Heme Biosynthesis ◽  
Biosynthesis Pathway ◽  
Efflux Transporter ◽  
Inherited Disease ◽  
Loss Of Function ◽  
Erythropoietic Protoporphyria

Erythropoietic protoporphyria (EPP) is an inherited disease caused by loss-of-function mutations of ferrochelatase, an enzyme in the heme biosynthesis pathway that converts protoporphyrin IX (PPIX) into heme. PPIX accumulation in patients with EPP leads to phototoxicity and hepatotoxicity, and there is no cure. Here, we demonstrated that the PPIX efflux transporter ABCG2 (also called BCRP) determines EPP-associated phototoxicity and hepatotoxicity. We found that ABCG2 deficiency decreases PPIX distribution to the skin and therefore prevents EPP-associated phototoxicity. We also found that ABCG2 deficiency protects against EPP-associated hepatotoxicity by modulating PPIX distribution, metabolism, and excretion. In summary, our work has uncovered an essential role of ABCG2 in the pathophysiology of EPP, which suggests the potential for novel strategies in the development of therapy for EPP.

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