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23-602: [REDACTED] Look up MMO in Wiktionary, the free dictionary. MMO may refer to: Entertainment [ edit ] Massively multiplayer online game , a video game that can be played by many people simultaneously Music Minus One , a record company in Westchester, New York Science and technology [ edit ] Methane monooxygenase , an enzyme Maximum operating Mach number Mercury Magnetospheric Orbiter ,

46-444: A beta-hairpin, which interacts with the soluble region of the B subunit. A conserved glutamate residue is thought to contribute to a metal center. Methane monooxygenases are found in methanotrophic bacteria , a class of bacteria that exist at the interface of aerobic (oxygen-containing) and anaerobic (oxygen-devoid) environments. One of the more widely studied bacteria of this type is Methylococcus capsulatus (Bath). This bacterium

69-658: A component of the Mercury mapper BepiColombo Mini-Mag Orion , a proposed type of spacecraft propulsion Mixed metal oxide , a class of materials often used in electrodes Other [ edit ] Means, motive, and opportunity , the "indicators of suspicion" Minimum municipal obligation , minimum contribution to a pension plan Maio Airport , in Cape Verde, IATA code Melton Mowbray railway station , England (National Rail station code MMO) Marine Management Organisation , UK government body Marine mammal observer ,

92-415: A four-center transition state and leading to a “hydrido-alkyl-Q” compound. As of 1999, the research suggests that the methane oxidation proceeds via a bound-radical mechanism. It was suggested that the transition state for the radical mechanism involves a torsion motion of the hydroxyl OH ligand before the methyl radical can add to the bridging hydroxyl ligand to form the alcohol. As the radical approaches,

115-460: A more active species, methanol . Other hydrocarbons are oxidized by MMOs, so a new hydroxylation catalyst based on the understanding of MMO systems could possibly make a more efficient use of the world supply of natural gas. This is a classic monooxygenase reaction in which two reducing equivalents from NAD(P)H are utilized to split the O-O bond of O2. One atom is reduced to water by a 2 e- reduction and

138-546: A professional in environmental consulting See also [ edit ] Military Merit Order (disambiguation) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title MMO . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=MMO&oldid=1207017979 " Category : Disambiguation pages Hidden categories: Short description

161-445: A range of substrates including ammonia, methane, halogenated hydrocarbons, and aromatic molecules. These enzymes are homotrimers composed of 3 subunits - A ( InterPro :  IPR003393 ), B ( InterPro :  IPR006833 ) and C ( InterPro :  IPR006980 ) and most contain two monocopper centers. The A subunit from Methylococcus capsulatus (Bath) resides primarily within the membrane and consists of 7 transmembrane helices and

184-443: A record company in Westchester, New York Science and technology [ edit ] Methane monooxygenase , an enzyme Maximum operating Mach number Mercury Magnetospheric Orbiter , a component of the Mercury mapper BepiColombo Mini-Mag Orion , a proposed type of spacecraft propulsion Mixed metal oxide , a class of materials often used in electrodes Other [ edit ] Means, motive, and opportunity ,

207-587: A semi bridging carboxylate, Glu 144, and a water molecule. The substrate must bind near the active site in order for the reaction to take place. Near to the iron centers, there are hydrophobic pockets. It is thought that here the methane binds and is held until needed. From the X-ray crystallography, there is no direct path to these packets. However, a slight conformation change in the Phe 188 or The 213 side-chains could allow access. This conformational change could be triggered by

230-410: Is different from Wikidata All article disambiguation pages All disambiguation pages MMO [REDACTED] Look up MMO in Wiktionary, the free dictionary. MMO may refer to: Entertainment [ edit ] Massively multiplayer online game , a video game that can be played by many people simultaneously Music Minus One ,

253-451: Is different from Wikidata All article disambiguation pages All disambiguation pages Methane monooxygenase There are two forms of MMO: the well-studied soluble form (sMMO) and the particulate form (pMMO) . The active site in sMMO contains a di-iron center bridged by an oxygen atom (Fe-O-Fe), whereas the active site in pMMO utilizes copper. Structures of both proteins have been determined by X-ray crystallography; however,

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276-428: Is under debate, is critical to the oxidizing species for MMO. There are two mechanisms suggested for the reaction between compound Q and the alkane: radical and nonradical. The radical mechanism starts with abstraction of the hydrogen atom from the substrate to form QH (the rate determining step), hydroxyl bridged compound Q and the free alkyl radical. The nonradical mechanism implies a concerted pathway, occurring via

299-453: The "indicators of suspicion" Minimum municipal obligation , minimum contribution to a pension plan Maio Airport , in Cape Verde, IATA code Melton Mowbray railway station , England (National Rail station code MMO) Marine Management Organisation , UK government body Marine mammal observer , a professional in environmental consulting See also [ edit ] Military Merit Order (disambiguation) Topics referred to by

322-417: The H atom of the alkane leave the coplanar tricoordinate O environment and bends upward to create a tetrahedral tetracoordinate O environment. The final step for this reaction is the elimination of the alcohol and the regeneration of the catalysts. There are a few ways in which this can occur. It could be a stepwise mechanism that starts with the elimination of the alcohol and an intermediate Fe-O-Fe core, and

345-450: The MMO shows that it is a dimer formed of three subunits, α2β2γ2. With 2.2 A resolution, the crystallography shows that MMO is a relatively flat molecule with the dimensions of 60 x 100 x 120 A. In addition, there is a wide canyon running along the dimer interface with an opening in the center of the molecule. Most of the protomers involves helices from the α and β subunits with no participation from

368-509: The MMOH red , the diiron centers react with the O 2 to form intermediate P. This intermediate is a peroxide species where the oxygens are bound symmetrically, suggested by spectroscopic studies. However, the structure is not known. Intermediate P then converts to intermediate Q, which was proposed to contain two antiferromagnetically coupled high-spin FeIV centers. This compound Q, the structure of which

391-607: The binding of a coupling protein and the activase. Upon reduction, one of the carboxylate ligands undergoes a “1,2 carboxylate” shift from behind a terminal monodentate ligand to a bridging ligand for the two irons, with the second oxygen coordinated to Fe 2. In the reduced form of MMOH red , the ligand environment for the Fe effectively becomes five coordinated, a form that permits the cluster to activate dioxygen. The two irons are at this point oxidized to FeIV and have changed from low-spin ferromagnetic to high-spin antiferromagnetic . From

414-459: The latter can eliminate the water and regenerate the enzyme through a 2e- reduction. On the other hand, it can start with a 2e- reduction process of bridging the O1 atom to give a water molecule, followed by elimination of the alcohol and regeneration of the enzyme. In addition, it is possible that there is a concerted mechanism whereby the elimination of the methanol occurs spontaneously with 2e- reduction of

437-414: The location and mechanism of the active site in pMMO is still poorly understood and is an area of active research. The particulate methane monooxygenase and related ammonia monooxygenase are integral membrane proteins, occurring in methanotrophs and ammonia oxidisers, respectively, which are thought to be related. These enzymes have a relatively wide substrate specificity and can catalyse the oxidation of

460-403: The same term [REDACTED] This disambiguation page lists articles associated with the title MMO . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=MMO&oldid=1207017979 " Category : Disambiguation pages Hidden categories: Short description

483-436: The second is incorporated into the substrate to yield methanol: CH 4 + O 2 + NAD(P)H + H -> CH 3 OH + NAD(P) + H 2 O Two forms of MMO have been found: soluble and particulate . The best characterized forms of soluble MMO contains three protein components: hydroxylase, the β unit, and the reductase. Each of which is necessary for effective substrate hydroxylation and NADH oxidation. X-ray crystallography of

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506-415: The γ subunit. Also, the interactions with the protomers resembles ribonucleotide reductase R2 protein dimer interaction, resembling a heart. Each iron has a six coordinate octahedral environment. The dinuclear iron centers are positioned in the α subunit. Each iron atoms are also coordinated to a histidine δN atom, Fe 1 to a His 147 and Fe 2 to His 246, Fe 1 is a ligated to a monodentate carboxylate, Glu 114,

529-453: Was discovered in the hot springs of Bath, England . Notably, strictly anaerobic methanotrophs may also harbour methane monooxygenases, although there are critical mismatches in the gene which prevent common methanotroph-seeking primers from matching. Methanotrophic bacteria play an essential role of cycling carbon through anaerobic sediments. The chemistry behind the cycling takes a chemically inert hydrocarbon, methane, and converts it to

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