Copper complexation of methanobactin isolated from Methylosinus trichosporium OB3b: pH-dependent speciation and modeling

Pesch, Marie-Laure; Christl, Iso; Hoffmann, M.; Kraemer, Stephan M.; Kretzschmar, Ruben

doi:10.1016/j.jinorgbio.2012.07.008

Cited by 19 publications

(48 citation statements)

References 26 publications

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“…Binding and Reduction of the Primary Metal, Copper mb binds both Cu 2ϩ and Cu 1ϩ , and the binding by mb appears to depend on pH (135,172) and on the ratio of Cu 2ϩ /Cu 1ϩ to mb (136,141,172) (Table 1). As discussed below, mb is able to complex both soluble and insoluble forms of Cu 1ϩ and Cu 2ϩ .…”

Section: Metal Binding Propertiesmentioning

confidence: 99%

“…Thermodynamic, spectral, and kinetic studies have been carried out on the addition of Cu 2ϩ to mb-OB3b and mb-SB2 (136,141). These studies (136,141,172) are complicated by the fact that mb rapidly reduces Cu 2ϩ to Cu 1ϩ . Since the oxidation state of copper responsible for the high bonding constant for experiments in which Cu 2ϩ has been added to apo-mbs is not known, we will indicate that a mixture of these oxidation states is present by using "Cu 2ϩ /Cu 1ϩ " from this point on.…”

Section: Metal Binding Propertiesmentioning

confidence: 99%

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Methanobactin and the Link between Copper and Bacterial Methane Oxidation

DiSpirito

Semrau

Murrell

et al. 2016

Microbiol Mol Biol Rev

128

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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Section: Metal Binding Propertiesmentioning

confidence: 99%

Section: Metal Binding Propertiesmentioning

confidence: 99%

Methanobactin and the Link between Copper and Bacterial Methane Oxidation

DiSpirito

Semrau

Murrell

et al. 2016

Microbiol Mol Biol Rev

128

157

View full text Add to dashboard Cite

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“…Although Mbns bind Cu(II) with lower affinity, generally calculated to be 10 11 -10 14 M -1 (25), binding is reductive, with conversion to Cu(I) within the first 10 min via an unknown mechanism, as confirmed by electron paramagnetic resonance and X-ray absorption spectroscopies (27,29,34,35). Under superstoichiometric copper conditions, a second copper binds, albeit with lower affinity and without reduction (29). Other stoichiometries are also observed under some conditions (29).…”

Section: Mbns As Metallophoresmentioning

confidence: 93%

“…The Cu(I) affinity is high enough that Mbn can liberate bio-unavailable copper from sources ranging from humic acids (30) to minerals (31) to borosilicate glass (32,33). Although Mbns bind Cu(II) with lower affinity, generally calculated to be 10 11 -10 14 M -1 (25), binding is reductive, with conversion to Cu(I) within the first 10 min via an unknown mechanism, as confirmed by electron paramagnetic resonance and X-ray absorption spectroscopies (27,29,34,35). Under superstoichiometric copper conditions, a second copper binds, albeit with lower affinity and without reduction (29).…”

Section: Mbns As Metallophoresmentioning

confidence: 96%

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Methanobactins: Maintaining copper homeostasis in methanotrophs and beyond

Kenney¹,

Rosenzweig

2018

Journal of Biological Chemistry

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Methanobactins (Mbns) are ribosomally produced, post-translationally modified natural products that bind copper with high affinity and specificity. Originally identified in methanotrophic bacteria, which have a high need for copper, operons encoding these compounds have also been found in many non-methanotrophic bacteria. The proteins responsible for Mbn biosynthesis include several novel enzymes. Mbn transport involves export through a multidrug efflux pump and reinternalization via a TonB-dependent transporter. Release of copper from Mbn and the molecular basis for copper regulation of Mbn production remain to be elucidated. Future work is likely to result in the identification of new enzymatic chemistry, opportunities for bioengineering and drug targeting of copper metabolism, and an expanded understanding of microbial metal homeostasis.Transition metals are key cofactors in metabolically important enzymes across all kingdoms of life (1). Nevertheless, careful control of cellular metal levels is required: a cellular surplus can limit viability due to oxidative stress (2), but metal starvation can also be fatal. Investigations of metal influx during conditions of metal scarcity have often been limited to iron, which is poorly bioavailable under aerobic conditions (3). Ironchelating natural products (siderophores) are secreted by many species, and iron from siderophores is incorporated into the cellular iron pool after re-internalization (4). While efflux has historically dominated studies of non-iron homeostasis, there is increasing evidence that similar systems exist for uptake of other metal ions (5, 6).

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Metallophores and Trace Metal Biogeochemistry

et al. 2014

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Trace metal limitation not only affects the biological function of organisms, but also the health of ecosystems and the global cycling of elements. The enzymatic machinery of microbes helps to drive critical biogeochemical cycles at the macroscale, and in many cases, the function of metalloenzyme-mediated processes may be limited by the scarcity of essential trace metals. In response to these nutrient limitations, some organisms employ a strategy of exuding metallophores, biogenic ligands that facilitate the uptake of metal ions. For example, bacterial, fungal, and graminaceous plant species are known to use Fe(III)-binding siderophores for nutrient acquisition, providing the best known and most thoroughly studied example of metallophores. However, recent breakthroughs have suggested or established the role of metallophores in the uptake of several other metallic nutrients. Furthermore, these metallophores may influence environmental trace metal fate and transport beyond nutrient acquisition. These discoveries have resulted in a deeper understanding of trace metal geochemistry and its relationship to the cycling of carbon and nitrogen in natural systems. In this review, we provide an overview of the current state of knowledge on the biogeochemistry of metallophores in trace metal acquisition, and explore established and potential metallophore systems.Electronic supplementary material The online version of this article (

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Copper complexation of methanobactin isolated from Methylosinus trichosporium OB3b: pH-dependent speciation and modeling

Cited by 19 publications

References 26 publications

Methanobactin and the Link between Copper and Bacterial Methane Oxidation

Methanobactin and the Link between Copper and Bacterial Methane Oxidation

Methanobactins: Maintaining copper homeostasis in methanotrophs and beyond

Metallophores and Trace Metal Biogeochemistry

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