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Molecules (Basel, Switzerland) Dec 2019This paper mainly focuses on the application of nanostructured MoO materials in both energy and environmental catalysis fields. MoO has wide tunability in bandgap, a... (Review)
Review
This paper mainly focuses on the application of nanostructured MoO materials in both energy and environmental catalysis fields. MoO has wide tunability in bandgap, a unique semiconducting structure, and multiple valence states. Due to the natural advantage, it can be used as a high-activity metal oxide catalyst, can serve as an excellent support material, and provide opportunities to replace noble metal catalysts, thus having broad application prospects in catalysis. Herein, we comprehensively summarize the crystal structure and properties of nanostructured MoO and highlight the recent significant research advancements in energy and environmental catalysis. Several current challenges and perspective research directions based on nanostructured MoO are also discussed.
Topics: Catalysis; Crystallography; Molecular Structure; Molybdenum; Nanostructures; Oxides; Photochemical Processes; Water
PubMed: 31861563
DOI: 10.3390/molecules25010018 -
Journal of Inorganic Biochemistry Mar 2023The rational design and functionalization of small, simple, and stable peptides scaffolds is an attractive avenue to mimic catalytic metal-centres of complex proteins,...
The rational design and functionalization of small, simple, and stable peptides scaffolds is an attractive avenue to mimic catalytic metal-centres of complex proteins, relevant for the design of metalloenzymes with environmental, biotechnological and health impacts. The de novo designed αDIV-L21C framework has a rubredoxin-like metal binding site and was used in this work to incorporate a Mo-atom. Thermostability studies using differential scanning calorimetry showed an increase of 4 °C in the melting temperature of the Mo-αDIV-L21C when compared to the apo-αDIV-L21C. Circular dichroism in the visible and far-UV regions corroborated these results showing that Mo incorporation provides stability to the peptide even though there were almost no differences observed in the secondary structure. A formal reduction potential of ∼ -408 mV vs. NHE, pH 7.6 was determined. Combining electrochemical results, EPR and UV-visible data we discuss the oxidation state of the molybdenum centre in Mo-αDIV-L21C and propose that is mainly in a Mo (VI) oxidation state.
Topics: Molybdenum; Rubredoxins; Metalloproteins; Oxidation-Reduction; Peptides
PubMed: 36603242
DOI: 10.1016/j.jinorgbio.2022.112096 -
Microbiology and Molecular Biology... Jun 2008The importance of molybdoenzymes is exemplified both by the debilitating and fatal human diseases caused by their deficiency and by their persistence throughout... (Review)
Review
The importance of molybdoenzymes is exemplified both by the debilitating and fatal human diseases caused by their deficiency and by their persistence throughout evolution. Here, we show that the protein fold of the molybdopyranopterin-containing domain of sulfite oxidase (the SUOX fold) can be found in all three domains of life. Analyses of sequence data and protein structure comparisons (secondary structure matching) show that the SUOX fold is found in enzymes that have quite distinct macromolecular architectures comprising one or more domains and sometimes subsidiary subunits. These are summarized as follows: (i) animal SUOXs that contain an N-terminal cytochrome b(5) domain and an SUOX fold fused to a C-terminal dimerization domain; (ii) plant SUOX that contains an SUOX fold fused to a C-terminal dimerization domain; (iii) the YedY protein from Escherichia coli, which comprises only the SUOX fold; (iv) the sulfite dehydrogenase from Starkeya novella that contains the SUOX fold, a dimerization domain, and an additional c-type cytochrome subunit; and (v) the plant-type nitrate reductases, exemplified by that of Pichia angusta, that contain an N-terminal SUOX fold, a dimerization domain, a cytochrome b(5) domain, and a C-terminal NADH binding flavin adenine dinucleotide-containing domain. We used the primary sequences of the proteins containing an SUOX fold to mine 559 sequences of related proteins. A phylogeny of a nonredundant subset of these sequences was generated, and the resultant clades were categorized by sequence motif analyses in the context of the available protein structures. Based on the motif analyses, cladistics, and domain conservations, we are able to postulate a plausible pathway of SUOX fold enzyme evolution.
Topics: Amino Acid Motifs; Amino Acid Sequence; Coenzymes; Conserved Sequence; Evolution, Molecular; Humans; Metalloproteins; Models, Molecular; Molybdenum; Molybdenum Cofactors; Phylogeny; Protein Folding; Protein Structure, Secondary; Pteridines; Pterins; Sequence Alignment; Sulfite Oxidase
PubMed: 18535145
DOI: 10.1128/MMBR.00041-07 -
The New Phytologist Feb 2018Nitrogen (N) fixation by free-living bacteria is a primary N input pathway in many ecosystems and sustains global plant productivity. Uncertainty exists over the...
Nitrogen (N) fixation by free-living bacteria is a primary N input pathway in many ecosystems and sustains global plant productivity. Uncertainty exists over the importance of N, phosphorus (P) and molybdenum (Mo) availability in controlling free-living N fixation rates. Here, we investigate the geographic occurrence and variability of nutrient constraints to free-living N fixation in the terrestrial biosphere. We compiled data from studies measuring free-living N fixation in response to N, P and Mo fertilizers. We used meta-analysis to quantitatively determine the extent to which N, P and Mo stimulate or suppress N fixation, and if environmental variables influence the degree of nutrient limitation of N fixation. Across our compiled dataset, free-living N fixation is suppressed by N fertilization and stimulated by Mo fertilization. Additionally, free-living N fixation is stimulated by P additions in tropical forests. These findings suggest that nutrient limitation is an intrinsic property of the biochemical demands of N fixation, constraining free-living N fixation in the terrestrial biosphere. These findings have implications for understanding the causes and consequences of N limitation in coupled nutrient cycles, as well as modeling and forecasting nutrient controls over carbon-climate feedbacks.
Topics: Ecosystem; Fertilizers; Forests; Geography; Molybdenum; Nitrogen; Nitrogen Fixation; Phosphorus; Plant Leaves
PubMed: 29165820
DOI: 10.1111/nph.14905 -
International Journal of Environmental... May 2021Molybdenum (Mo) microbial bioreduction is a phenomenon that is beginning to be recognized globally as a tool for the remediation of molybdenum toxicity. Molybdenum... (Review)
Review
Molybdenum (Mo) microbial bioreduction is a phenomenon that is beginning to be recognized globally as a tool for the remediation of molybdenum toxicity. Molybdenum toxicity continues to be demonstrated in many animal models of spermatogenesis and oogenesis, particularly those of ruminants. The phenomenon has been reported for more than 100 years without a clear understanding of the reduction mechanism, indicating a clear gap in the scientific knowledge. This knowledge is not just fundamentally important-it is specifically important in applications for bioremediation measures and the sustainable recovery of metal from industrial or mine effluent. To date, about 52 molybdenum-reducing bacteria have been isolated globally. An increasing number of reports have also been published regarding the assimilation of other xenobiotics. This phenomenon is likely to be observed in current and future events in which the remediation of xenobiotics requires microorganisms capable of degrading or transforming multi-xenobiotics. This review aimed to comprehensively catalogue all of the characterizations of molybdenum-reducing microorganisms to date and identify future opportunities and improvements.
Topics: Animals; Biodegradation, Environmental; Molybdenum; Oxidation-Reduction
PubMed: 34071757
DOI: 10.3390/ijerph18115731 -
Journal of Bacteriology May 1993The alternative, heterometal-free nitrogenase of Rhodobacter capsulatus is repressed by traces of molybdenum in the medium. Strains carrying mutations located downstream... (Comparative Study)
Comparative Study
The alternative, heterometal-free nitrogenase of Rhodobacter capsulatus is repressed by traces of molybdenum in the medium. Strains carrying mutations located downstream of nifB copy II were able to express the alternative nitrogenase even in the presence of high molybdate concentrations. DNA sequence analysis of a 5.5-kb fragment of this region revealed six open reading frames, designated modABCD, mopA, and mopB. The gene products of modB and modC are homologous to ChlJ and ChlD of Escherichia coli and represent an integral membrane protein and an ATP-binding protein typical of high-affinity transport systems, respectively. ModA and ModD exhibited no homology to known proteins, but a leader peptide characteristic of proteins cleaved during export to the periplasm is present in ModA, indicating that ModA might be a periplasmic molybdate-binding protein. The MopA and MopB proteins showed a high degree of amino acid sequence homology to each other. Both proteins contained a tandem repeat of a domain encompassing 70 amino acid residues, which had significant sequence similarity to low-molecular-weight molybdenum-pterin-binding proteins from Clostridium pasteurianum. Compared with that for the parental nifHDK deletion strain, the molybdenum concentrations necessary to repress the alternative nitrogenase were increased 4-fold in a modD mutant and 500-fold in modA, modB, and modC mutants. No significant inhibition of the heterometal-free nitrogenase by molybdate was observed for mopA mopB double mutants. The uptake of molybdenum by mod and mop mutants was estimated by measuring the activity of the conventional molybdenum-containing nitrogenase. Molybdenum transport was not affected in a mopA mopB double mutant, whereas strains carrying lesions in the binding-protein-dependent transport system were impaired in molybdenum uptake.
Topics: Amino Acid Sequence; Bacterial Proteins; Base Sequence; Biological Transport; Carrier Proteins; Chromosome Mapping; DNA Mutational Analysis; Dose-Response Relationship, Drug; Enzyme Repression; Genes, Bacterial; Membrane Transport Proteins; Molecular Sequence Data; Molybdenum; Nitrogenase; Pterins; Rhodobacter capsulatus; Sequence Analysis, DNA; Sequence Homology, Amino Acid
PubMed: 8491722
DOI: 10.1128/jb.175.10.3031-3042.1993 -
Scientific Reports Jul 2022Molybdenum disulfide (MoS) screen-printed working electrodes were developed for dopamine (DA) electrochemical sensing. MoS working electrodes were prepared from high...
Molybdenum disulfide (MoS) screen-printed working electrodes were developed for dopamine (DA) electrochemical sensing. MoS working electrodes were prepared from high viscosity screen-printable inks containing various concentrations and sizes of MoS particles and ethylcellulose binder. Rheological properties of MoS inks and their suitability for screen-printing were analyzed by viscosity curve, screen-printing simulation and oscillatory modulus. MoS inks were screen-printed onto conductive FTO (Fluorine-doped Tin Oxide) substrates. Optical microscopy and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX) analysis were used to characterize the homogeneity, topography and thickness of the screen-printed MoS electrodes. The electrochemical performance was assessed through differential pulse voltammetry. Results showed an extensive linear detection of dopamine from 1 µM to 300 µM (R = 0.996, sensitivity of 5.00 × 10 A μM), with the best limit of detection being 246 nM. This work demonstrated the possibility of simple, low-cost and rapid preparation of high viscosity MoS ink and their use to produce screen-printed FTO/MoS electrodes for dopamine detection.
Topics: Dopamine; Electrochemical Techniques; Electrodes; Molybdenum
PubMed: 35831476
DOI: 10.1038/s41598-022-16187-2 -
Polyoxometalate Nanoparticles as a Potential Glioblastoma Therapeutic via Lipid-Mediated Cell Death.International Journal of Molecular... Jul 2022Polyoxometalate nanoparticles (POMs) are a class of compounds made up of multiple transition metals linked together using oxygen atoms. POMs commonly include group 6...
Polyoxometalate nanoparticles (POMs) are a class of compounds made up of multiple transition metals linked together using oxygen atoms. POMs commonly include group 6 transition metals, with two of the most common forms using molybdenum and tungsten. POMs are suggested to exhibit antimicrobial effects. In this study, we developed two POM preparations to study anti-cancer activity. We found that Mo-POM (NH)MoO) and W-POM (HPWO) have anti-cancer effects on glioblastoma cells. Both POMs induced morphological changes marked by membrane swelling and the presence of multinucleated cells that may indicate apoptosis induction along with impaired cell division. We also observed significant increases in lipid oxidation events, suggesting that POMs are redox-active and can catalyze detrimental oxidation events in glioblastoma cells. Here, we present preliminary indications that molybdenum polyoxometalate nanoparticles may act like ferrous iron to catalyze the oxidation of phospholipids. These preliminary results suggest that Mo-POMs (NH)MoO) and W-POMs (HPWO) may warrant further investigation into their utility as adjunct cancer therapies.
Topics: Anions; Cell Death; Glioblastoma; Humans; Lipids; Molybdenum; Nanoparticles; Polyelectrolytes; Transition Elements; Tungsten Compounds
PubMed: 35897839
DOI: 10.3390/ijms23158263 -
The Journal of Nutrition Jan 2007The objectives of this study were to determine physiologic adaptations that occur when humans are exposed to a wide range of molybdenum intake levels and to identify the...
The objectives of this study were to determine physiologic adaptations that occur when humans are exposed to a wide range of molybdenum intake levels and to identify the pathways that are influenced by dietary intake. Four males consumed each of 5 daily molybdenum intakes of 22, 72, 121, 467, and 1490 microg/d (0.23, 0.75, 1.3, 4.9, and 15.5 micromol/d) for 24 d each. During each treatment period, oral and intravenous doses of (100)Mo and (97)Mo were administered. Serial plasma, urine, and fecal samples were analyzed for labeled and unlabeled molybdenum. Compartmental modeling was used to determine rates of distribution and elimination at each dietary intake level. Three pathways were sensitive to daily molybdenum intake. With increasing intake, absorption and urinary molybdenum excretion increased, whereas the fraction deposited in tissues decreased. Kinetic analysis suggested a daily intake of 115-120 microg/d (1.20-1.25 micromol/d) would maintain initial plasma molybdenum levels at their prestudy values and that their prestudy dietary intake was well above the Recommended Dietary Allowance of 45 microg/d. The physiological adaptations to changing intake that the model demonstrated may help prevent molybdenum deficiency and toxicity.
Topics: Administration, Oral; Adult; Analysis of Variance; Humans; Kinetics; Male; Models, Biological; Molybdenum
PubMed: 17182798
DOI: 10.1093/jn/137.1.37 -
Molecules (Basel, Switzerland) Oct 2022The need for fresh and conveniently treated water has become a major concern in recent years. Molybdenum disulfide (MoS) nanomaterials are attracting attention in... (Review)
Review
The need for fresh and conveniently treated water has become a major concern in recent years. Molybdenum disulfide (MoS) nanomaterials are attracting attention in various fields, such as energy, hydrogen production, and water decontamination. This review provides an overview of the recent developments in MoS-based nanomaterials for water treatment via adsorption and photodegradation. Primary attention is given to the structure, properties, and major methods for the synthesis and modification of MoS, aiming for efficient water-contaminant removal. The combination of MoS with other components results in nanocomposites that can be separated easily or that present enhanced adsorptive and photocatalytic properties. The performance of these materials in the adsorption of heavy metal ions and organic contaminants, such as dyes and drugs, is reviewed. The review also summarizes current progress in the photocatalytic degradation of various water pollutants, using MoS-based nanomaterials under UV-VIS light irradiation. MoS-based materials showed good activity after several reuse cycles and in real water scenarios. Regarding the ecotoxicity of the MoS, the number of studies is still limited, and more work is needed to effectively evaluate the risks of using this nanomaterial in water treatment.
Topics: Photolysis; Adsorption; Molybdenum; Water Pollutants; Water Pollutants, Chemical; Nanocomposites; Metals, Heavy; Coloring Agents; Hydrogen
PubMed: 36296375
DOI: 10.3390/molecules27206782