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Science (New York, N.Y.) Mar 2020Many disease pathologies can be understood through the elucidation of localized biomolecular networks, or microenvironments. To this end, enzymatic proximity labeling...
Many disease pathologies can be understood through the elucidation of localized biomolecular networks, or microenvironments. To this end, enzymatic proximity labeling platforms are broadly applied for mapping the wider spatial relationships in subcellular architectures. However, technologies that can map microenvironments with higher precision have long been sought. Here, we describe a microenvironment-mapping platform that exploits photocatalytic carbene generation to selectively identify protein-protein interactions on cell membranes, an approach we term MicroMap (μMap). By using a photocatalyst-antibody conjugate to spatially localize carbene generation, we demonstrate selective labeling of antibody binding targets and their microenvironment protein neighbors. This technique identified the constituent proteins of the programmed-death ligand 1 (PD-L1) microenvironment in live lymphocytes and selectively labeled within an immunosynaptic junction.
Topics: B7-H1 Antigen; Catalysis; Cell Membrane; Cellular Microenvironment; Energy Transfer; Humans; Jurkat Cells; Lymphocytes; Methane; Photochemical Processes; Protein Interaction Mapping; Protein Interaction Maps; Ultraviolet Rays
PubMed: 32139536
DOI: 10.1126/science.aay4106 -
Nature Nov 2019Methane is a powerful greenhouse gas and is targeted for emissions mitigation by the US state of California and other jurisdictions worldwide. Unique opportunities for...
Methane is a powerful greenhouse gas and is targeted for emissions mitigation by the US state of California and other jurisdictions worldwide. Unique opportunities for mitigation are presented by point-source emitters-surface features or infrastructure components that are typically less than 10 metres in diameter and emit plumes of highly concentrated methane. However, data on point-source emissions are sparse and typically lack sufficient spatial and temporal resolution to guide their mitigation and to accurately assess their magnitude. Here we survey more than 272,000 infrastructure elements in California using an airborne imaging spectrometer that can rapidly map methane plumes. We conduct five campaigns over several months from 2016 to 2018, spanning the oil and gas, manure-management and waste-management sectors, resulting in the detection, geolocation and quantification of emissions from 564 strong methane point sources. Our remote sensing approach enables the rapid and repeated assessment of large areas at high spatial resolution for a poorly characterized population of methane emitters that often appear intermittently and stochastically. We estimate net methane point-source emissions in California to be 0.618 teragrams per year (95 per cent confidence interval 0.523-0.725), equivalent to 34-46 per cent of the state's methane inventory for 2016. Methane 'super-emitter' activity occurs in every sector surveyed, with 10 per cent of point sources contributing roughly 60 per cent of point-source emissions-consistent with a study of the US Four Corners region that had a different sectoral mix. The largest methane emitters in California are a subset of landfills, which exhibit persistent anomalous activity. Methane point-source emissions in California are dominated by landfills (41 per cent), followed by dairies (26 per cent) and the oil and gas sector (26 per cent). Our data have enabled the identification of the 0.2 per cent of California's infrastructure that is responsible for these emissions. Sharing these data with collaborating infrastructure operators has led to the mitigation of anomalous methane-emission activity.
Topics: California; Environmental Monitoring; Greenhouse Effect; Manure; Methane; Natural Gas; Oil and Gas Industry; Petroleum; Waste Management; Wastewater
PubMed: 31695210
DOI: 10.1038/s41586-019-1720-3 -
Chemical Society Reviews Mar 2021Methanotrophic bacteria represent a potential route to methane utilization and mitigation of methane emissions. In the first step of their metabolic pathway, aerobic... (Review)
Review
Methanotrophic bacteria represent a potential route to methane utilization and mitigation of methane emissions. In the first step of their metabolic pathway, aerobic methanotrophs use methane monooxygenases (MMOs) to activate methane, oxidizing it to methanol. There are two types of MMOs: a particulate, membrane-bound enzyme (pMMO) and a soluble, cytoplasmic enzyme (sMMO). The two MMOs are completely unrelated, with different architectures, metal cofactors, and mechanisms. The more prevalent of the two, pMMO, is copper-dependent, but the identity of its copper active site remains unclear. By contrast, sMMO uses a diiron active site, the catalytic cycle of which is well understood. Here we review the current state of knowledge for both MMOs, with an emphasis on recent developments and emerging hypotheses. In addition, we discuss obstacles to developing expression systems, which are needed to address outstanding questions and to facilitate future protein engineering efforts.
Topics: Bacteria; Bacterial Proteins; Catalytic Domain; Metals; Methane; Oxidation-Reduction; Oxygenases; Protein Engineering
PubMed: 33491685
DOI: 10.1039/d0cs01291b -
Mass Spectrometry Reviews Jul 2022This review is devoted to ion spectroscopy studies of complexes relevant for the understanding of methane activation with metal ions and clusters. Methane activation... (Review)
Review
This review is devoted to ion spectroscopy studies of complexes relevant for the understanding of methane activation with metal ions and clusters. Methane activation starts with the formation of a complex with a metal ion. The degree of the interaction between an intact methane molecule and the ion can be monitored by the perturbations of C-H stretch vibrations in the methane molecule. Binding mediated by the electrostatic interaction results in a η type coordination of methane. In contrast, binding governed by orbital interactions results in a η type coordination of methane. We further review the spectroscopic characterization of activation products of metal-methane reactions, such as the metal-carbene and carbyne products resulting from the interaction of selected 5d metals with methane. The focus of recent research in the field has shifted towards the investigation of interactions between methane and metal clusters. We show examples highlighting that metal clusters can be more reactive in methane activation reactions.
Topics: Ions; Mass Spectrometry; Metals; Methane; Spectrum Analysis
PubMed: 34008884
DOI: 10.1002/mas.21698 -
World Journal of Microbiology &... Aug 2022Microorganisms act as both the source and sink of methane, a potent greenhouse gas, thus making a significant contribution to the environment as an important driver of... (Review)
Review
Microorganisms act as both the source and sink of methane, a potent greenhouse gas, thus making a significant contribution to the environment as an important driver of climate change. The rhizosphere and phyllosphere of plants growing in natural (mangroves) and artificial wetlands (flooded agricultural ecosystems) harbor methane-utilizing bacteria that oxidize methane at the source and reduce its net flux. For several decades, microorganisms have been used as biofertilizers to promote plant growth. However, now their role in reducing net methane flux, especially from flooded agricultural ecosystems is gaining momentum globally. Research in this context has mainly focused on taxonomic aspects related to methanotrophy among diverse bacterial genera, and environmental factors that govern methane utilization in natural and artificial wetland ecosystems. In the last few decades, concerted efforts have been made to develop multifunctional microbial inoculants that can oxidize methane and alleviate greenhouse gas emissions, as well as promote plant growth. In this context, combinations of taxonomic groups commonly found in rice paddies and those used as biofertilizers are being explored. This review deals with methanotrophy among diverse bacterial domains, factors influencing methane-utilizing ability, and explores the potential of novel methane-utilizing microbial consortia with plant growth-promoting traits in flooded ecosystems.
Topics: Agriculture; Bacteria; Ecosystem; Greenhouse Gases; Methane; Soil; Wetlands
PubMed: 35922575
DOI: 10.1007/s11274-022-03331-3 -
Journal of Zhejiang University....Methane is the simplest hydrocarbon, consisting of one carbon atom and four hydrogen atoms. It is abundant in marsh gas, livestock rumination, and combustible ice.... (Review)
Review
Methane is the simplest hydrocarbon, consisting of one carbon atom and four hydrogen atoms. It is abundant in marsh gas, livestock rumination, and combustible ice. Little is known about the use of methane in human disease treatment. Current research indicates that methane is useful for treating several diseases including ischemia and reperfusion injury, and inflammatory diseases. The mechanisms underlying the protective effects of methane appear primarily to involve anti-oxidation, anti-inflammation, and anti-apoptosis. In this review, we describe the beneficial effects of methane on different diseases, summarize possible mechanisms by which methane may act in these conditions, and discuss the purpose of methane production in hypoxic conditions. Then we propose several promising directions for the future research.
Topics: Antioxidants; Apoptosis; Humans; Inflammation; Ischemia; Methane; Reperfusion Injury
PubMed: 32748575
DOI: 10.1631/jzus.B1900629 -
Topics in Current Chemistry (Cham) Nov 2019Over the past decade, the combination of visible light photocatalysis and organocatalysis has made remarkable progress in modern chemical synthesis. In these dual... (Review)
Review
Over the past decade, the combination of visible light photocatalysis and organocatalysis has made remarkable progress in modern chemical synthesis. In these dual catalysis system, photocatalysts or photosensitizers absorb visible light to induce their photoexcited states which can activate unreactive substrates via electron or energy transfer mechanisms, and organocatalysts are usually employed to regulate the chemical reactivity of the other substrates. By doing so, two reactive species react with each in a selective-especially enantioselective-way, to provide the final products. This article summarizes the recent development of cooperative catalysis by the combination of organocatalysis and photocatalysis in asymmetric organic synthesis. These reactions are classified according to the manner of activation of the organocatalysts. Enamine/iminium catalysts are used to activate unreactive carbonyl molecules. Nucleophilic catalysts including nitrogen heterocycle carbene catalysts and tertiary amine catalysts are employed to reverse the reactivity of electrodeficient substrates including aldehydes and enals. Chiral Brønsted acid catalysts are used to activate substrates by forming key H-bonding complexes between substrates and catalysts.
Topics: Aldehydes; Alkenes; Amines; Catalysis; Imines; Light; Methane; Stereoisomerism
PubMed: 31728771
DOI: 10.1007/s41061-019-0265-0 -
Medical Gas Research 2023Methane has shown protective effects on a variety of diseases. Among these, neurological diseases have attracted much attention. However, there are many different... (Review)
Review
Methane has shown protective effects on a variety of diseases. Among these, neurological diseases have attracted much attention. However, there are many different indicators and application methods of methane in the treatment of neurological diseases. In this review, we summarize the indicators related to the protective effects of methane and evaluate the preparation and administration of methane. Thus, we hope to offer available indicators and effective ways to produce and administer methane in future research.
Topics: Methane; Nervous System Diseases; Humans
PubMed: 37077112
DOI: 10.4103/2045-9912.372663 -
Annual Review of Microbiology Sep 2022Methane is one of the most important greenhouse gases on Earth and holds an important place in the global carbon cycle. Archaea are the only organisms that use... (Review)
Review
Methane is one of the most important greenhouse gases on Earth and holds an important place in the global carbon cycle. Archaea are the only organisms that use methanogenesis to produce energy and rely on the methyl-coenzyme M reductase complex (Mcr). Over the last decade, new results have significantly reshaped our view of the diversity of methane-related pathways in the Archaea. Many new lineages that synthesize or use methane have been identified across the whole archaeal tree, leading to a greatly expanded diversity of substrates and mechanisms. In this review, we present the state of the art of these advances and how they challenge established scenarios of the origin and evolution of methanogenesis, and we discuss the potential trajectories that may have led to this strikingly wide range of metabolisms.
Topics: Archaea; Methane; Oxidation-Reduction; Phylogeny
PubMed: 35759872
DOI: 10.1146/annurev-micro-041020-024935 -
Nature Chemistry Jul 2022The σ-alkane complexes of transition metals, which contain an essentially intact alkane molecule weakly bound to the metal, have been well established as crucial...
The σ-alkane complexes of transition metals, which contain an essentially intact alkane molecule weakly bound to the metal, have been well established as crucial intermediates in the activation of the strong C-H σ-bonds found in alkanes. Methane, the simplest alkane, binds even more weakly than larger alkanes. Here we report an example of a long-lived methane complex formed by directly binding methane as an incoming ligand to a reactive organometallic complex. Photo-ejection of carbon monoxide from a cationic osmium-carbonyl complex dissolved in an inert hydrofluorocarbon solvent saturated with methane at -90 °C affords an osmium(II) complex, [η-CpOs(CO)(CH)], containing methane bound to the metal centre. Nuclear magnetic resonance (NMR) spectroscopy confirms the identity of the σ-methane complex and shows that the four protons of the metal-bound methane are in rapid exchange with each other. The methane ligand has a characteristically shielded H NMR resonance (δ -2.16), and the highly shielded carbon resonance (δ -56.3) shows coupling to the four attached protons (J = 127 Hz). The methane complex has an effective half-life of about 13 hours at -90 °C.
Topics: Alkanes; Ligands; Metals; Methane; Osmium; Protons
PubMed: 35469008
DOI: 10.1038/s41557-022-00929-w