Category Ranking
98%
Total Visits
921
Avg Visit Duration
2 minutes
Citations
20
Article Abstract
Subunits Rpo3 and Rpb3/AC40 of RNA polymerase (RNAP) from many archaea and some eukaryotes, respectively, contain a ferredoxin-like domain (FLD) predicted to bind one or two [4Fe-4S] clusters postulated to play a role in regulating the assembly of RNAP. To test this hypothesis, the two [4Fe-4S] cluster Rpo3 from Methanosarcina acetivorans was modified to generate variants that lack the FLD or each [4Fe-4S] cluster. Viability of gene replacement mutants revealed that neither the FLD nor the ability of the FLD to bind either [4Fe-4S] cluster is essential. Nevertheless, each mutant demonstrated impaired growth due to significantly lower RNAP activity when compared to wild type. Affinity purification of tagged Rpo3 variants from M. acetivorans strains revealed that neither the FLD nor each [4Fe-4S] cluster is required for the formation of a Rpo3/11 heterodimer, the first step in the assembly of RNAP. However, the association of the Rpo3/11 heterodimer with catalytic subunits Rpo2' and Rpo1″ was diminished by the removal of the FLD and each cluster, with the loss of cluster 1 having a more substantial effect than the loss of cluster 2. These results reveal that the FLD and [4Fe-4S] clusters, particularly cluster 1, are key determinants in the post Rpo3/11 heterodimer assembly of RNAP in M. acetivorans.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5300874 | PMC |
| http://dx.doi.org/10.1002/mbo3.399 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Differential ligation alters electronic state and coupling signals of iron-sulfur clusters in flavin-based electron bifurcation.
J Inorg Biochem
September 2025
National Renewable Energy Laboratory, Biosciences Center, Golden, CO, USA. Electronic address:
Flavin-based electron bifurcation (FBEB) is employed by microorganisms for controlling pools of redox equivalents by reversibly splitting electron pairs into high- and low-energy levels from an initial midpoint potential. Our ability to harness this phenomenon is crucial for biocatalytic design which is limited by our understanding of energy coupling in the bifurcation system. In Pyrococcus furiosus, FBEB is carried out by the NADH-dependent ferredoxin:NADP-oxidoreductase (NfnSL), coupling the uphill reduction of ferredoxin in NfnL to the downhill reduction of NAD in NfnS from oxidation of NADPH.
View Article and Find Full Text PDFResonance Raman Spectroscopic Study of the Unusual [4Fe-4S] Cluster of IspH, the Last Enzyme of the Methylerythritol Phosphate Pathway for Terpenoid Biosynthesis.
Chembiochem
August 2025
Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg CNRS, Strasbourg, 67000, France.
IspH is the last enzyme of the methylerythritol phosphate pathway. It catalyzes the reductive dehydroxylation of (E)-4-hydroxy-3-methyl-but-2-en-1-yl diphosphate into isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), which are precursors for the biosynthesis of terpenoids, essential molecules for the survival of all living organisms. This pathway is absent in humans, making it a promising target for drug discovery.
View Article and Find Full Text PDFIron-Sulfur-Mediated C-S Bond Formation: Mechanistic Insights from the state-crossing tRNA Methylthiolation by the Radical SAM Enzyme MiaB.
Chemistry
September 2025
Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory for Chemical Power Source and Green Catalysis, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China.
The radical S-adenosylmethionine (SAM) enzyme MiaB is a bifunctional catalyst that mediates the posttranscriptional methylthiolation of N-isopentenyladenosine (iA37) at position 37 in tRNA. Herein, density functional calculations were employed to elucidate the two stages of MiaB-catalyzed modification: methylation and sulfur insertion at the C position of iA37. MiaB contains two iron-sulfur clusters: a radical SAM cluster ([4Fe-4S]) and an auxiliary cluster ([3Fe-4S]).
View Article and Find Full Text PDFStructural basis for anaerobic alkane activation by a multisubunit glycyl radical enzyme.
Proc Natl Acad Sci U S A
August 2025
Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139.
X-succinate synthases (XSSs) are glycyl radical enzymes (GREs) that catalyze the addition of hydrocarbons to fumarate via radical chemistry, thereby activating them for microbial metabolism. To date, the only structurally characterized XSS is benzylsuccinate synthase (BSS), which functionalizes toluene. A distinct subclass of XSSs acts on saturated hydrocarbons, which possess much stronger C(sp)-H bonds than toluene, suggesting mechanistic and structural differences from BSS.
View Article and Find Full Text PDFIron overload exaggerates renal ischemia-reperfusion injury by promoting tubular cuproptosis via interrupting function of LIAS.
Redox Biol
August 2025
Department of Kidney Transplantation, Zhongshan Hospital, Fudan University, China; Shanghai Key Laboratory of Organ Transplantation, Shanghai, 200032, China; Shanghai Medical Collage, Fudan University, Shanghai, China. Electronic address:
Renal ischemia-reperfusion injury (RIRI), a major contributor to acute kidney injury (AKI) and delayed graft function (DGF), is closely associated with dysregulation of metal ion homeostasis. Although copper and iron metabolism exhibit interconnected regulatory pathways, the temporal dynamics and functional interplay of these metal ions in RIRI pathogenesis remain poorly understood. Our study demonstrates that cuproptosis and ferroptosis, two distinct forms of cell death induced by metal ion overload, occur simultaneously within 6 h after reperfusion.
View Article and Find Full Text PDF