Stimulation of Methanotroph Activity by Cu-Substituted Borosilicate Glass

Kulczycki, Ezra; Fowle, David A.; Kenward, Paul A.; Leslie, Karla; Graham, David W.; Roberts, J. A. Fraser

doi:10.1080/01490451003614971

Cited by 16 publications

(22 citation statements)

References 49 publications

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“…Even though mb binds Cu(II), evidence shows that the copper when bound is reduced to Cu(I). In fact, recent studies indicate that mb exhibits differential efficiency with respect to the rates and amounts of copper it can extract from different copper mineral sources (Knapp et al 2006;Kulczycki et al , 2010Chi Fru et al 2011).…”

Section: Cycling Of Metals By Chalkophores Produced By Methanotrophsmentioning

confidence: 96%

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

Fru¹

2011

Geomicrobiology Journal

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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.

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Section: Cycling Of Metals By Chalkophores Produced By Methanotrophsmentioning

confidence: 96%

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

Fru¹

2011

Geomicrobiology Journal

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“…31 These findings provide insight into Mb function in nature and have been extended to correlate copper content of glass with methane oxidation rates of M. trichosporium OB3b. 59 In these experiments, methane depletion was measured in the presence of manufactured borosilicate glasses with 0–800 ppm Cu, with maximum rates observed at 80 and 200 ppm, and lowest rates at 0 and 800 ppm. The methane oxidation rates are comparable to those measured using soluble copper, suggesting that insoluble copper can support methanotroph growth in nature.…”

Section: Copper Uptake Functionmentioning

confidence: 99%

Chemistry and Biology of the Copper Chelator Methanobactin

Kenney

Rosenzweig

2011

ACS Chem. Biol.

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Methanotrophic bacteria, organisms that oxidize methane, produce a small copper chelating molecule called methanobactin (Mb). Mb binds Cu(I) with high affinity and is hypothesized to mediate copper acquisition from the environment. Recent advances in Mb characterization include revision of the chemical structure of Mb from Methylosinus trichosporium OB3b and further investigation of its biophysical properties. In addition, Mb production by several other methanotroph strains has been investigated and preliminary characterization suggests diversity in chemical composition. Initial clues into Mb biosynthesis have been obtained by identification of a putative precursor gene in the M. trichosporium OB3b genome. Finally, direct uptake of intact Mb into the cytoplasm of M. trichosporium OB3b cells has been demonstrated and studies of the transport mechanism have been initiated. Taken together, these advances represent significant progress and set the stage for exciting new research directions.

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“…mbs have been shown to solubilize and bind insoluble forms of Cu 1ϩ under anaerobic conditions (141) and to extract Cu from copper minerals (176), humic material (177), and glass (178). The ability of mbs to extract copper from copper-containing minerals as well as other organic molecules should be considered in modeling bioavailable sources of copper (179)(180)(181)(182)(183).…”

Section: Cumentioning

confidence: 99%

Methanobactin and the Link between Copper and Bacterial Methane Oxidation

DiSpirito

Semrau

Murrell

et al. 2016

Microbiol Mol Biol Rev

127

157

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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.

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Stimulation of Methanotroph Activity by Cu-Substituted Borosilicate Glass

Cited by 16 publications

References 49 publications

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

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

Chemistry and Biology of the Copper Chelator Methanobactin

Methanobactin and the Link between Copper and Bacterial Methane Oxidation

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