Copper-binding properties and structures of methanobactins from methylosinus trichosporium ob3b

Abdelnasser El Ghazouani, Arnaud Basle, Susan Firbank, Charles Knapp, Joe Gray, David Graham, Christopher Dennison

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Methanobactins (mbs) are a class of copper-binding peptides produced by aerobic methane oxidizing bacteria (methanotrophs) that have been linked to the substantial copper needs of these environmentally important microorganisms. The only characterized mbs are those from Methylosinus trichosporium OB3b and Methylocystis strain SB2. M. trichosporium OB3b produces a second mb (mb-Met), which is missing the C-terminal Met residue from the full-length form (FL-mb). The as-isolated copper-loaded mbs bind Cu(I). The absence of the Met has little influence on the structure of the Cu(I) site, and both molecules mediate switchover from the soluble iron methane mono-oxygenase to the particulate copper-containing enzyme in M. trichosporium OB3b cells. Cu(II) is reduced in the presence of the mbs under our experimental conditions, and the disulfide plays no role in this process. The Cu(I) affinities of these molecules are extremely high with values of (6−7) × 1020 M−1 determined at pH ≥ 8.0. The affinity for Cu(I) is 1 order of magnitude lower at pH 6.0. The reduction potentials of copper-loaded FL-mb and mb-Met are 640 and 590 mV respectively, highlighting the strong preference for Cu(I) and indicating different Cu(II) affinities for the two forms. Cleavage of the disulfide bridge results in a decrease in the Cu(I) affinity to 9 × 1018 M−1 at pH 7.5. The two thiolates can also bind Cu(I), albeit with much lower affinity ( 3 × 1015 M−1 at pH 7.5). The high affinity of mbs for Cu(I) is consistent with a physiological role in copper uptake and protection.
LanguageEnglish
JournalInorganic Chemistry
Volume50
Issue number4
DOIs
Publication statusPublished - 21 Jan 2011

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affinity
Copper
copper
Methane
disulfides
Disulfides
methane
Oxygenases
Molecules
microorganisms
Microorganisms
bacteria
particulates
peptides
methanobactin
enzymes
molecules
cleavage
Bacteria
Iron

Keywords

  • inorganic chemistry
  • copper binding properties
  • methanobactins

Cite this

El Ghazouani, Abdelnasser ; Basle, Arnaud ; Firbank, Susan ; Knapp, Charles ; Gray, Joe ; Graham, David ; Dennison, Christopher. / Copper-binding properties and structures of methanobactins from methylosinus trichosporium ob3b. In: Inorganic Chemistry. 2011 ; Vol. 50, No. 4.
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abstract = "Methanobactins (mbs) are a class of copper-binding peptides produced by aerobic methane oxidizing bacteria (methanotrophs) that have been linked to the substantial copper needs of these environmentally important microorganisms. The only characterized mbs are those from Methylosinus trichosporium OB3b and Methylocystis strain SB2. M. trichosporium OB3b produces a second mb (mb-Met), which is missing the C-terminal Met residue from the full-length form (FL-mb). The as-isolated copper-loaded mbs bind Cu(I). The absence of the Met has little influence on the structure of the Cu(I) site, and both molecules mediate switchover from the soluble iron methane mono-oxygenase to the particulate copper-containing enzyme in M. trichosporium OB3b cells. Cu(II) is reduced in the presence of the mbs under our experimental conditions, and the disulfide plays no role in this process. The Cu(I) affinities of these molecules are extremely high with values of (6−7) × 1020 M−1 determined at pH ≥ 8.0. The affinity for Cu(I) is 1 order of magnitude lower at pH 6.0. The reduction potentials of copper-loaded FL-mb and mb-Met are 640 and 590 mV respectively, highlighting the strong preference for Cu(I) and indicating different Cu(II) affinities for the two forms. Cleavage of the disulfide bridge results in a decrease in the Cu(I) affinity to 9 × 1018 M−1 at pH 7.5. The two thiolates can also bind Cu(I), albeit with much lower affinity ( 3 × 1015 M−1 at pH 7.5). The high affinity of mbs for Cu(I) is consistent with a physiological role in copper uptake and protection.",
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Copper-binding properties and structures of methanobactins from methylosinus trichosporium ob3b. / El Ghazouani, Abdelnasser; Basle, Arnaud; Firbank, Susan; Knapp, Charles; Gray, Joe; Graham, David; Dennison, Christopher.

In: Inorganic Chemistry, Vol. 50, No. 4, 21.01.2011.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Copper-binding properties and structures of methanobactins from methylosinus trichosporium ob3b

AU - El Ghazouani, Abdelnasser

AU - Basle, Arnaud

AU - Firbank, Susan

AU - Knapp, Charles

AU - Gray, Joe

AU - Graham, David

AU - Dennison, Christopher

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N2 - Methanobactins (mbs) are a class of copper-binding peptides produced by aerobic methane oxidizing bacteria (methanotrophs) that have been linked to the substantial copper needs of these environmentally important microorganisms. The only characterized mbs are those from Methylosinus trichosporium OB3b and Methylocystis strain SB2. M. trichosporium OB3b produces a second mb (mb-Met), which is missing the C-terminal Met residue from the full-length form (FL-mb). The as-isolated copper-loaded mbs bind Cu(I). The absence of the Met has little influence on the structure of the Cu(I) site, and both molecules mediate switchover from the soluble iron methane mono-oxygenase to the particulate copper-containing enzyme in M. trichosporium OB3b cells. Cu(II) is reduced in the presence of the mbs under our experimental conditions, and the disulfide plays no role in this process. The Cu(I) affinities of these molecules are extremely high with values of (6−7) × 1020 M−1 determined at pH ≥ 8.0. The affinity for Cu(I) is 1 order of magnitude lower at pH 6.0. The reduction potentials of copper-loaded FL-mb and mb-Met are 640 and 590 mV respectively, highlighting the strong preference for Cu(I) and indicating different Cu(II) affinities for the two forms. Cleavage of the disulfide bridge results in a decrease in the Cu(I) affinity to 9 × 1018 M−1 at pH 7.5. The two thiolates can also bind Cu(I), albeit with much lower affinity ( 3 × 1015 M−1 at pH 7.5). The high affinity of mbs for Cu(I) is consistent with a physiological role in copper uptake and protection.

AB - Methanobactins (mbs) are a class of copper-binding peptides produced by aerobic methane oxidizing bacteria (methanotrophs) that have been linked to the substantial copper needs of these environmentally important microorganisms. The only characterized mbs are those from Methylosinus trichosporium OB3b and Methylocystis strain SB2. M. trichosporium OB3b produces a second mb (mb-Met), which is missing the C-terminal Met residue from the full-length form (FL-mb). The as-isolated copper-loaded mbs bind Cu(I). The absence of the Met has little influence on the structure of the Cu(I) site, and both molecules mediate switchover from the soluble iron methane mono-oxygenase to the particulate copper-containing enzyme in M. trichosporium OB3b cells. Cu(II) is reduced in the presence of the mbs under our experimental conditions, and the disulfide plays no role in this process. The Cu(I) affinities of these molecules are extremely high with values of (6−7) × 1020 M−1 determined at pH ≥ 8.0. The affinity for Cu(I) is 1 order of magnitude lower at pH 6.0. The reduction potentials of copper-loaded FL-mb and mb-Met are 640 and 590 mV respectively, highlighting the strong preference for Cu(I) and indicating different Cu(II) affinities for the two forms. Cleavage of the disulfide bridge results in a decrease in the Cu(I) affinity to 9 × 1018 M−1 at pH 7.5. The two thiolates can also bind Cu(I), albeit with much lower affinity ( 3 × 1015 M−1 at pH 7.5). The high affinity of mbs for Cu(I) is consistent with a physiological role in copper uptake and protection.

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