The gene clusters encoding soluble methane monooxygenase (sMMO) and particulate methane monooxygenase (pMMO) were cloned and sequenced from a new type I methanotroph, Methylovulum miyakonense HT12. The sMMO gene cluster consisted of the structural genes mmoXYBZDC, the regulatory genes mmoG and mmoR and another ORF orf1. Transcriptional analysis revealed that these sMMO genes were transcribed as a single unit from a σ(54) -dependent promoter located upstream of mmoX. In the pMMO gene cluster, the pmoCAB operon was under the control of a σ(70) -dependent promoter. The organization of each MMO operon was largely conserved with that of the previously described methanotrophs. However, unlike other methanotrophs, M. miyakonense HT12 harbored only a single copy of the pmoCAB gene. These data provide new insights into the structure of MMO genes.
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http://dx.doi.org/10.1111/j.1574-6968.2010.02101.x | 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 PDFChem Rec
January 2025
Bioinspired & Biomimetic Inorganic Chemistry Laboratory, Department of Chemistry, National Institute of Technology Calicut, Kozhikode, Kerala, 673601, India.
Direct methane to methanol conversion is a dream reaction in industrial chemistry, which takes inspiration from the biological methanol production catalysed by methane monooxygenase enzymes (MMOs). Over the years, extensive studies have been conducted on this topic by bioengineering the MMOs, and tailoring methods to isolate the MMOs in the active form. Similarly, remarkable achievements have been noted in other methane activation strategies such as the use of heterogeneous catalysts or molecular catalysts.
View Article and Find Full Text PDFDalton Trans
January 2025
Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioicho, Chiyoda-ku, Tokyo 102-8554, Japan.
The Ru(IV,IV), Ru(III,IV), and Ru(III,III) complexes with the doubly oxido- and/or hydroxido-bridged diamond core {Ru(μ-O(H))}, bridged by an η:η:μ-type bidentate sulfato ligand, [{Ru(L)}(μ-O)(μ-OSO)] ( = 1: [III,IV]; = 2: [IV,IV]), [{Ru(L)}(μ-O)(μ-OH)(μ-OSO)] ([III,IV_1H]), and [{Ru(L)}(μ-OH)(μ-OSO)] ([III,III_2H]) (L = ethylbis(2-pyridylmethyl)amine), were synthesised as ClO-salts, and their crystal and electronic structures investigated. The corresponding hydrogencarbonato-bridged Ru(III,III) complex, [{Ru(L)}(μ-OH)(μ-OCOH)] ([III,III(HCO3)_2H]), was also prepared and its crystallographic and electronic structures compared to those of the sulfato-bridged system, [III,III_2H]. All the sulfato-bridged complexes isolated were confirmed in the Pourbaix diagram, wherein the redox potential was plotted as a function of pH.
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 PDFBioresour Technol
December 2024
Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore. Electronic address:
The urgency to mitigate greenhouse gas emissions has driven interest in sustainable biogas utilization. This study investigates a 1 L enclosed membrane photobioreactor (MPBR) using a microalgae-methanotroph coculture for biogas capture. Operating with a hydraulic and solid retention time of 7 days and a biogas loading rate of 2.
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