Effect of copper on membrane lipids and on methane monooxygenase activity of Methylococcus capsulatus (Bath)

Peltola, Petri; Priha, Petri; Laakso, Simo

doi:10.1007/bf00249029

Cited by 13 publications

(16 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Comparison of cells expressing pMMO cultured with 1 and 59 M copper showed a 15-fold increase in the three pMMO polypeptides, an 18-fold increase in pMMO transcript concentration, and a 2.6-fold increase in the concentration of fatty acids per cell. Previous results from this and S. Chan's laboratory have shown that when measured per milligram of membrane protein, the concentration of pMMO was essentially constant with increasing copper concentrations (32,36,52). To resolve the difference between the results presented above and those from previous studies, ultrastructural examination (Fig.…”

Section: Vol 185 2003 Pmmo-ndh Complex From M Capsulatus Bath 5757mentioning

confidence: 71%

The Membrane-Associated Methane Monooxygenase (pMMO) and pMMO-NADH:Quinone Oxidoreductase Complex from Methylococcus capsulatus Bath

et al. 2003

View full text Add to dashboard Cite

Improvements in purification of membrane-associated methane monooxygenase (pMMO) have resulted in preparations of pMMO with activities more representative of physiological rates: i.e., >130 nmol ⅐ min ؊1 ⅐ mg of protein ؊1 . Altered culture and assay conditions, optimization of the detergent/protein ratio, and simplification of the purification procedure were responsible for the higher-activity preparations. Changes in the culture conditions focused on the rate of copper addition. To document the physiological events that occur during copper addition, cultures were initiated in medium with cells expressing soluble methane monooxygenase (sMMO) and then monitored for morphological changes, copper acquisition, fatty acid concentration, and pMMO and sMMO expression as the amended copper concentration was increased from 0 (approximately 0.3 M) to 95 M. The results demonstrate that copper not only regulates the metabolic switch between the two methane monooxygenases but also regulates the level of expression of the pMMO and the development of internal membranes. With respect to stabilization of cell-free pMMO activity, the highest cell-free pMMO activity was observed when copper addition exceeded maximal pMMO expression. Optimization of detergent/ protein ratios and simplification of the purification procedure also contributed to the higher activity levels in purified pMMO preparations. Finally, the addition of the type 2 NADH:quinone oxidoreductase complex (NADH dehydrogenase [NDH]) from M. capsulatus Bath, along with NADH and duroquinol, to enzyme assays increased the activity of purified preparations. The NDH and NADH were added to maintain a high duroquinol/duroquinone ratio.Methanotrophs are a group of gram-negative bacteria that utilize methane or methanol as the sole source of carbon and energy (1,20). The initial oxidation of methane to methanol is catalyzed by methane monooxygenase (MMO). In some methanotrophs, two different MMOs can be expressed, depending on the copper concentration during growth (11, 37, 39): a soluble cytoplasmic MMO (sMMO) and a membrane-associated, or particulate, MMO (pMMO). In cells cultured under low copper/biomass ratios (Յ0.9 nmol of Cu/mg of cell protein), the sMMO is expressed (20, 28). Cells cultured under higher copper/biomass ratios express pMMO, and there is no detectable sMMO expression (35,43). While sMMO is a wellcharacterized enzyme that consists of a hydroxylase component composed of three polypeptides and a hydroxo-bridged binuclear iron cluster-an NADH-dependent reductase component composed of one polypeptide containing both FAD and [Fe 2 S 2 ] cofactors and a regulatory polypeptide (18,26,27,31,47)-information on the molecular properties of pMMO is limited due to the instability of pMMO in cell-free fractions.Purification of the pMMO has been reported from Methylococcus capsulatus Bath (2,25,33, 52) and M. trichosporium

show abstract

Section: Vol 185 2003 Pmmo-ndh Complex From M Capsulatus Bath 5757mentioning

confidence: 71%

The Membrane-Associated Methane Monooxygenase (pMMO) and pMMO-NADH:Quinone Oxidoreductase Complex from Methylococcus capsulatus Bath

et al. 2003

View full text Add to dashboard Cite

show abstract

“…Lipid contents of cells are also elevated in the presence of copper (Peltola et al 1993). Cellular pMMO content experienced a rise, concomitant with copper bioavailability than was the case for oxygen (Davis et al 1986).…”

Section: Copper In Methanotrophic Bacterial Growthmentioning

confidence: 92%

“…Because copper bioavailability enhances pMMO activity, methane oxidation rates and biomass yields also increase proportionally as more copper becomes available in the growth medium, when methane is nonlimiting (Prior and Dalton, 1985;Peltola et al 1993;Nielsen et al 1997;Murrell et al 2000). This is assumed here to reflect what also happens in the natural environment.…”

Section: Copper In Methanotrophic Bacterial Growthmentioning

confidence: 97%

“…The methanotrophic bacteria have an even stronger need for copper in their metabolism because the form of MMO expressed is tightly regulated by copper bioavailability (Prior and Dalton, 1985;Leak et al 1986;Peltola et al 1993;Nielsen et al 1997;Murrell et al 2000;Knapp et al 2007). When soluble copper is >0.8 µM (50.8 mg L −1 ), relative to cell biomass, pMMO is expressed.…”

Section: Copper In Methanotrophic Bacterial Growthmentioning

confidence: 99%

See 1 more Smart Citation

Copper Biogeochemistry: A Cornerstone in Aerobic Methanotrophic Bacterial Ecology and Activity?

Fru¹

2011

Geomicrobiology Journal

View full text Add to dashboard Cite

Two distinct enzymatic pathways are implicated in the key step whereby methane is converted to methanol by the aerobic methane oxidizing bacteria (methanotrophs). These two enzymes, soluble and particulate methane monooxygenases (sMMO and pMMO, respectively), are evolutionarily unrelated. However, the activities of these enzymes are tightly linked to copper, which is central to the switch responsible for regulating MMO expression. When bioavailable copper exceeds a certain threshold relative to cell biomass, pMMO is expressed and its activity maintained by available copper. Below this threshold or when copper is entirely absent, sMMO catalyses methane oxidation. The individual forms of MMO degrade methane and hydrocarbon pollutants at different rates and efficiencies. Typically, pMMO is by up to 30% more efficient at methane degradation as opposed to sMMO which is more effective in the transformation of a wide range of hazardous hydrocarbons than pMMO. Consequently, the type of MMO expressed influences the ability of methanotrophs to effectively act as biological filters curtailing methane input into the atmosphere and for bioremediation. Because of the crucial requirement of copper some methanotrophs produce chalkophores specifically involved in copper trafficking. These chalkophores can in addition bind a variety of earth metals with varying affinities. Methanotrophs can also extract copper from various minerals thereby implicating them in weathering processes. The abundance of the methanotrophic bacteria in nature implies a significant amount of copper and iron in the geobiosphere that form the core of the MMOs, is regularly cycled through these organisms. This discussion is focused on methanotrohphic bacterial population dynamics observed during growth on various copper species, to extrapolate their impact on geomicrobiological processes.

show abstract

“…Several studies have demonstrated a direct correlation between intracytoplasmic membrane development and expression of pMMO in methanotrophs (33,35,66,109,114,194). As stated above, mbnA plays a secondary role in the regulation of both the membrane-bound and soluble MMO (see Regulation of Gene Expression above).…”

Section: Membrane Developmentmentioning

confidence: 93%

Methanobactin and the Link between Copper and Bacterial Methane Oxidation

DiSpirito

Semrau

Murrell

et al. 2016

Microbiol Mol Biol Rev

132

157

View full text Add to dashboard Cite

SUMMARYMethanobactins (mbs) are low-molecular-mass (<1,200 Da) copper-binding peptides, or chalkophores, produced by many methane-oxidizing bacteria (methanotrophs). These molecules exhibit similarities to certain iron-binding siderophores but are expressed and secreted in response to copper limitation. Structurally, mbs are characterized by a pair of heterocyclic rings with associated thioamide groups that form the copper coordination site. One of the rings is always an oxazolone and the second ring an oxazolone, an imidazolone, or a pyrazinedione moiety. The mb molecule originates from a peptide precursor that undergoes a series of posttranslational modifications, including (i) ring formation, (ii) cleavage of a leader peptide sequence, and (iii) in some cases, addition of a sulfate group. Functionally, mbs represent the extracellular component of a copper acquisition system. Consistent with this role in copper acquisition, mbs have a high affinity for copper ions. Following binding, mbs rapidly reduce Cu2+to Cu1+. In addition to binding copper, mbs will bind most transition metals and near-transition metals and protect the host methanotroph as well as other bacteria from toxic metals. Several other physiological functions have been assigned to mbs, based primarily on their redox and metal-binding properties. In this review, we examine the current state of knowledge of this novel type of metal-binding peptide. We also explore its potential applications, how mbs may alter the bioavailability of multiple metals, and the many roles mbs may play in the physiology of methanotrophs.

show abstract

Effect of copper on membrane lipids and on methane monooxygenase activity of Methylococcus capsulatus (Bath)

Cited by 13 publications

References 19 publications

The Membrane-Associated Methane Monooxygenase (pMMO) and pMMO-NADH:Quinone Oxidoreductase Complex from Methylococcus capsulatus Bath

The Membrane-Associated Methane Monooxygenase (pMMO) and pMMO-NADH:Quinone Oxidoreductase Complex from Methylococcus capsulatus Bath

Copper Biogeochemistry: A Cornerstone in Aerobic Methanotrophic Bacterial Ecology and Activity?

Methanobactin and the Link between Copper and Bacterial Methane Oxidation

Contact Info

Product

Resources

About