The particulate methane monooxygenase (pMMO) from Methylosinus trichosporium OB3b was partially purified and characterized by measuring the effects of reducing agents and additives, and the stability of pMMO was studied. Duroquinol was a suitable reducing agent, and pMMO was stabilized by bovine serum albumin (BSA). Among the additives, the copper (II) ion stimulated pMMO at low concentration and inhibited at high concentration. The optimum conditions for pMMO activity were as follows: 45 degrees C, pH 6.5 and 55 mM 3-morpholinopropanesulfonic acid (MOPS) buffer, and the rate of propene epoxide formation was 13.6 nmol min-1 mg-1 protein. ESR spectra indicate that the copper cluster in the membrane fraction is reduced by duroquinol and oxidized by dioxygen. The result suggests that the copper cluster is contained in the active site of pMMO.
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http://dx.doi.org/10.1023/a:1009278216452 | DOI Listing |
Dalton Trans
January 2025
Department of Computational Chemistry, Lund University, Chemical Centre, P. O. Box 124, SE-221 00 Lund, Sweden.
Particulate methane monooxygenase (pMMO) is the most efficient of the two groups of enzymes that can hydroxylate methane. The enzyme is membrane bound and therefore hard to study experimentally. For that reason, there is still no consensus regarding the location and nature of the active site.
View Article and Find Full Text PDFPLoS One
January 2025
Environmental Molecular Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America.
Coastal wetlands, including freshwater systems near large lakes, rapidly bury carbon, but less is known about how they transport carbon either to marine and lake environments or to the atmosphere as greenhouse gases (GHGs) such as carbon dioxide and methane. This study examines how GHG production and organic matter (OM) mobility in coastal wetland soils vary with the availability of oxygen and other terminal electron acceptors. We also evaluated how OM and redox-sensitive species varied across different size fractions: particulates (0.
View Article and Find Full Text PDFEnviron Sci Technol
January 2025
Department of Atmospheric Sciences, University of Utah, Salt Lake City, Utah 84112, United States.
Methane (CH) is a greenhouse gas with a global warming potential 81.2 times higher than carbon dioxide (CO). The intentional emission of oxidants into the atmosphere has been proposed as a geoengineering solution to accelerate the oxidation of CH to CO, thereby reducing surface warming.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Departments of Molecular Biosciences and of Chemistry, Northwestern University, Evanston, IL 60208.
Methane- and ammonia-oxidizing bacteria play key roles in the global carbon and nitrogen cycles, respectively. These bacteria use homologous copper membrane monooxygenases to accomplish the defining chemical transformations of their metabolisms: the oxidations of methane to methanol by particulate methane monooxygenase (pMMO) and ammonia to hydroxylamine by ammonia monooxygenase (AMO), enzymes of prime interest for applications in mitigating climate change. However, investigations of these enzymes have been hindered by the need for disruptive detergent solubilization prior to structure determination, confounding studies of pMMO and precluding studies of AMO.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Department of Environmental Engineering, Pukyong National University, Busan 48513, Republic of Korea.
Rapid industrialization and the influx of human resources have led to the establishment of industrial complexes near urban areas, exposing residents to various air pollutants. This has led to a decline in air quality, impacting neighboring residential areas adversely, which highlights the urgent need to monitor air pollution in these areas. Recent advancements in technology, such as Solar Occultation Flux (SOF) and Sky Differential Optical Absorption Spectroscopy (SkyDOAS) used as remote sensing techniques and mobile extraction Fourier Transform Infrared Spectrometry (MeFTIR) used as an in situ technique, now offer enhanced precision in estimating the pollutant emission flux and identifying primary sources.
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