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Molecules (Basel, Switzerland) Jul 2022A concise review is provided of the contributions that various spectroscopic methods have made to our understanding of the physical and electronic structures of... (Review)
Review
A concise review is provided of the contributions that various spectroscopic methods have made to our understanding of the physical and electronic structures of mononuclear molybdenum enzymes. Contributions to our understanding of the structure and function of each of the major families of these enzymes is considered, providing a perspective on how spectroscopy has impacted the field.
Topics: Electron Spin Resonance Spectroscopy; Molybdenum
PubMed: 35956757
DOI: 10.3390/molecules27154802 -
Journal of the American Chemical Society Aug 2022Splitting of N via six-electron reduction and further functionalization to value-added products is one of the most important and challenging chemical transformations in...
Splitting of N via six-electron reduction and further functionalization to value-added products is one of the most important and challenging chemical transformations in N fixation. However, most N splitting approaches rely on strong chemical or electrochemical reduction to generate highly reactive metal species to bind and activate N, which is often incompatible with functionalizing agents. Catalytic and sustainable N splitting to produce metal nitrides under mild conditions may create efficient and straightforward methods for N-containing organic compounds. Herein, we present that a readily available and nonredox (-Bu)NBr can promote N-splitting with a Mo(III) platform. Both experimental and theoretical mechanistic studies suggest that simple X (X = Br, Cl, etc.) anions could induce the disproportionation of Mo[N()Ar] at the early stage of the catalysis to generate a catalytically active {Mo[N()Ar]} species. The quintet Mo species prove to be more favorable for N fixation kinetically and thermodynamically, compared with the quartet Mo counterpart. Especially, computational studies reveal a distinct heterovalent {Mo-N-Mo} dimeric intermediate for the N≡N triple bond cleavage.
Topics: Catalysis; Electrons; Molybdenum
PubMed: 35882019
DOI: 10.1021/jacs.2c01507 -
Nature Communications Sep 2019The recent decline in energy, size and complexity scaling of traditional von Neumann architecture has resurrected considerable interest in brain-inspired computing....
The recent decline in energy, size and complexity scaling of traditional von Neumann architecture has resurrected considerable interest in brain-inspired computing. Artificial neural networks (ANNs) based on emerging devices, such as memristors, achieve brain-like computing but lack energy-efficiency. Furthermore, slow learning, incremental adaptation, and false convergence are unresolved challenges for ANNs. In this article we, therefore, introduce Gaussian synapses based on heterostructures of atomically thin two-dimensional (2D) layered materials, namely molybdenum disulfide and black phosphorus field effect transistors (FETs), as a class of analog and probabilistic computational primitives for hardware implementation of statistical neural networks. We also demonstrate complete tunability of amplitude, mean and standard deviation of the Gaussian synapse via threshold engineering in dual gated molybdenum disulfide and black phosphorus FETs. Finally, we show simulation results for classification of brainwaves using Gaussian synapse based probabilistic neural networks.
Topics: Disulfides; Molybdenum; Nanotechnology; Neural Networks, Computer; Normal Distribution; Transistors, Electronic
PubMed: 31519885
DOI: 10.1038/s41467-019-12035-6 -
Chemical Reviews Jun 2020Biological nitrogen fixation is catalyzed by the enzyme nitrogenase, which facilitates the cleavage of the relatively inert triple bond of N. Nitrogenase is most... (Review)
Review
Biological nitrogen fixation is catalyzed by the enzyme nitrogenase, which facilitates the cleavage of the relatively inert triple bond of N. Nitrogenase is most commonly associated with the molybdenum-iron cofactor called FeMoco or the M-cluster, and it has been the subject of extensive structural and spectroscopic characterization over the past 60 years. In the late 1980s and early 1990s, two "alternative nitrogenase" systems were discovered, isolated, and found to incorporate V or Fe in place of Mo. These systems are regulated by separate gene clusters; however, there is a high degree of structural and functional similarity between each nitrogenase. Limited studies with the V- and Fe-nitrogenases initially demonstrated that these enzymes were analogously active as the Mo-nitrogenase, but more recent investigations have found capabilities that are unique to the alternative systems. In this review, we will discuss the reactivity, biosynthetic, and mechanistic proposals for the alternative nitrogenases as well as their electronic and structural properties in comparison to the well-characterized Mo-dependent system. Studies over the past 10 years have been particularly fruitful, though key aspects about V- and Fe-nitrogenases remain unexplored.
Topics: Models, Molecular; Molybdenum; Nitrogen; Nitrogen Fixation; Nitrogenase
PubMed: 32129988
DOI: 10.1021/acs.chemrev.9b00704 -
Journal of Materials Chemistry. B Jun 2022The development of nanomaterial-based antibiotics can be the most potent alternative due to the increasing resistance against conventional antibiotics. However, one of...
The development of nanomaterial-based antibiotics can be the most potent alternative due to the increasing resistance against conventional antibiotics. However, one of the important parameters in the development of antibacterial agents is their Gram selectivity, which has been seldomly explored in the case of nano-antibiotics. The multimodal action of surface-functionalized nanomaterials can exhibit strain selectivity and enhanced antibacterial activity. Herein, we designed a Gram-selective antibacterial system based on two-dimensional molybdenum disulphide (2D-MoS) functionalized with different proportions of positively and negatively charged ligands. Two representative ESKAPE pathogenic strains, , Gram-positive methicillin-resistant (MRSA) and Gram-negative () were considered to evaluate the selective antibacterial activity. The mechanistic insight behind selectivity was established by evaluating the degree of membrane depolarization together with oxidative stress. The selective generation of intracellular reactive oxygen species (ROS) together with membrane depolarization contributed to the selective killing of the pathogenic bacteria. Gram selectivity was achieved by simply controlling the surface functionality based on the different cell wall compositions and structures of bacterial strains. The interplay between polyvalent electrostatic and non-covalent interactions was mainly responsible for damaging the cell membrane. Furthermore, to establish the antibacterial mechanism, we performed extracellular and intracellular reactive oxidative stress, membrane depolarization and permeabilization assays. In summary, we prepared simple and efficient Gram-selective 2D-MoS-based antibacterial agents, which can be extended to other nano-antibiotic systems.
Topics: Anti-Bacterial Agents; Methicillin-Resistant Staphylococcus aureus; Molybdenum; Pseudomonas aeruginosa
PubMed: 35640626
DOI: 10.1039/d2tb00361a -
Chembiochem : a European Journal of... Mar 2024The connection between 3d (Cu) and 4d (Mo) via the "Mo-S-Cu" unit is called Mo-Cu antagonism. Biology offers case studies of such interactions in metalloproteins such as... (Review)
Review
The connection between 3d (Cu) and 4d (Mo) via the "Mo-S-Cu" unit is called Mo-Cu antagonism. Biology offers case studies of such interactions in metalloproteins such as Mo/Cu-CO Dehydrogenases (Mo/Cu-CODH), and Mo/Cu Orange Protein (Mo/Cu-ORP). The CODH significantly maintains the CO level in the atmosphere below the toxic level by converting it to non-toxic CO for respiring organisms. Several models were synthesized to understand the structure-function relationship of these native enzymes. However, this interaction was first observed in ruminants, and they convert molybdate (MoO ) into tetrathiomolybdate (MoS ; TTM), reacting with cellular Cu to yield biological unavailable Mo/S/Cu cluster, then developing Cu-deficiency diseases. These findings inspire the use of TTM as a Cu-sequester drug, especially for treating Cu-dependent human diseases such as Wilson diseases (WD) and cancer. It is well known that a balanced Cu homeostasis is essential for a wide range of biological processes, but negative consequence leads to cell toxicity. Therefore, this review aims to connect the Mo-Cu antagonism in metalloproteins and anti-copper therapy.
Topics: Humans; Copper; Molybdenum; Metalloproteins
PubMed: 38205937
DOI: 10.1002/cbic.202300679 -
Journal of Controlled Release :... Aug 2022Bacterial infections are yet another serious threat to human health. Misuse or overuse of conventional antibiotics has led to the arrival of various super resistant... (Review)
Review
Bacterial infections are yet another serious threat to human health. Misuse or overuse of conventional antibiotics has led to the arrival of various super resistant bacteria along with many serious side effects to human body. In this exigent circumstance, the use of nanomaterial based antibacterial agents is one of the most appropriate solutions to fight against bacteria thereby causing an inhibition to bacterial proliferation. Recent studies show that, due to the large surface area, high biocompatibility, strong near-infrared (NIR) absorption and low cytotoxicity, molybdenum disulphide (MoS), an extraordinary member in the transition metal dichalcogenides (TMDs) is extensively explored in the obliteration of many drug resistant bacteria, photothermal therapy and drug delivery. MoS based nanomaterials can effectively prevent bacterial growth through many mechanisms. Through this review, we have tried to provide an inclusive knowledge on the recent progress of antibacterial studies in MoS based nanomaterials including MoS nanosheets, nanoflowers, quantum dot (QD), hybrid nanocomposites and polymer nanocomposites. Moreover, toxicity of MoS based nanomaterials is described at the end of the review.
Topics: Anti-Bacterial Agents; Disulfides; Drug Delivery Systems; Humans; Molybdenum; Nanocomposites; Polymers
PubMed: 35662576
DOI: 10.1016/j.jconrel.2022.05.047 -
Metal Ions in Life Sciences Mar 2020The last 20 years have seen a dramatic increase in our mechanistic understanding of the reactions catalyzed by pyranopterin Mo and W enzymes. These enzymes possess a...
The last 20 years have seen a dramatic increase in our mechanistic understanding of the reactions catalyzed by pyranopterin Mo and W enzymes. These enzymes possess a unique cofactor (Moco) that contains a novel ligand in bioinorganic chemistry, the pyranopterin ene-1,2-dithiolate. A synopsis of Moco biosynthesis and structure is presented, along with our current understanding of the role Moco plays in enzymatic catalysis. Oxygen atom transfer (OAT) reactivity is discussed in terms of breaking strong metal-oxo bonds and the mechanism of OAT catalyzed by enzymes of the sulfite oxidase (SO) family that possess dioxo Mo(VI) active sites. OAT reactivity is also discussed in members of the dimethyl sulfoxide (DMSO) reductase family, which possess des-oxo Mo(IV) sites. Finally, we reveal what is known about hydride transfer reactivity in xanthine oxidase (XO) family enzymes and the formate dehydrogenases. The formal hydride transfer reactivity catalyzed by xanthine oxidase family enzymes is complex and cleaves substrate C-H bonds using a mechanism that is distinct from monooxygenases. The chapter primarily highlights developments in the field that have occurred since ~2000, which have contributed to our collective structural and mechanistic understanding of the three canonical pyranopterin Mo enzymes families: XO, SO, and DMSO reductase.
Topics: Biocatalysis; Molybdenum; Sulfite Oxidase; Tungsten
PubMed: 32851830
DOI: 10.1515/9783110589757-015 -
ChemSusChem Dec 2015Photocatalytic water splitting using powered semiconductors as photocatalysts represents a promising strategy for clean, low-cost, and environmentally friendly... (Review)
Review
Photocatalytic water splitting using powered semiconductors as photocatalysts represents a promising strategy for clean, low-cost, and environmentally friendly production of H2 utilizing solar energy. The loading of noble-metal cocatalysts on semiconductors can significantly enhance the solar-to-H2 conversion efficiency. However, the high cost and scarcity of noble metals counter their extensive utilization. Therefore, the use of alternative cocatalysts based on non-precious metal materials is pursued. Nanosized MoS2 cocatalysts have attracted considerable attention in the last decade as a viable alternative to improve solar-to-H2 conversion efficiency because of its superb catalytic activity, excellent stability, low cost, availability, environmental friendliness, and chemical inertness. In this perspective, the design, structures, synthesis, and application of MoS2 -based composite photocatalysts for solar H2 generation are summarized, compared, and discussed. Finally, this Review concludes with a summary and remarks on some challenges and opportunities for the future development of MoS2 -based photocatalysts.
Topics: Catalysis; Coloring Agents; Disulfides; Hydrogen; Molybdenum; Photochemical Processes; Sunlight
PubMed: 26586523
DOI: 10.1002/cssc.201501203 -
ACS Applied Bio Materials Jul 2023Molybdenum-based nanomaterials with variable oxidation states can be developed as nanozyme catalysts. In this work, we developed a one-pot method for the preparation of...
Molybdenum-based nanomaterials with variable oxidation states can be developed as nanozyme catalysts. In this work, we developed a one-pot method for the preparation of molybdenum disulfide assisted by protein. Protamine was used as a cationic template to link molybdate anions and form complexes. During hydrothermal synthesis, protamine can affect the nucleation process of molybdenum disulfide and inhibit their aggregation, which facilitates the fabrication of small-sized molybdenum disulfide nanoparticles. Moreover, the abundant amino/guanidyl groups of protamine could both physically adsorb and chemically bond to molybdenum disulfide and further modulate the crystal structures. The optimized size and crystalline structure enabled a higher exposure of active sites, which enhanced the peroxidase-like activity of molybdenum disulfide/protamine nanocomposites. Meanwhile, the antibacterial activity of protamine was retained in the molybdenum disulfide/protamine nanocomposites, which could synergize with the peroxidase-like activity of molybdenum disulfide to kill bacteria. Therefore, the molybdenum disulfide/protamine nanocomposites are good candidates for antibacterial agents with lower chances of antimicrobial resistance. This study establishes an easy way to design artificial nanozymes by compounding suitable components.
Topics: Molybdenum; Biomimetics; Nanocomposites; Protamines; Peroxidases; Anti-Bacterial Agents
PubMed: 37317061
DOI: 10.1021/acsabm.3c00341