Regulation of bacterial methane oxidation: transcription of the soluble methane mono-oxygenase operon of Methylococcus capsulatus (Bath) is repressed by copper ions.
نویسندگان
چکیده
Methane is oxidized to methanol by the enzyme methane mono-oxygenase (MMO) in methanotrophic bacteria. In previous work, this multicomponent enzyme system has been extensively characterized at the biochemical and molecular level. Copper ions have been shown to irreversibly inhibit MMO activity in vivo and in vitro, but the effect of copper ions on transcription of the genes encoding the soluble (cytoplasmic) MMO (sMMO) has not previously been investigated. To examine more closely the regulation of bacterial methane oxidation and to determine the role of copper in this process, we have investigated transcriptional regulation of the sMMO gene cluster in the methanotrophic bacterium Methylococcus capsulatus (Bath). Using Northern blot analysis and primer extension experiments, it was shown that the six ORFs of the sMMO gene cluster are organized as an operon and the transcripts produced upon expression of this operon have been identified. The synthesis of these transcripts was under control of a single copper-regulated promoter, which is as yet not precisely defined.
منابع مشابه
Steady-state kinetic analysis of soluble methane mono-oxygenase from Methylococcus capsulatus (Bath).
A steady-state kinetic analysis of purified soluble methane mono-oxygenase of Methylococcus capsulatus (Bath) was performed. The enzyme was found to follow a concerted-substitution mechanism. Methane binds to the enzyme followed by NADH, which reacts to yield reduced enzyme and NAD+. The reduced enzyme-methane complex binds O2 to give a second ternary complex, which breaks down to release water...
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Methylococcus capsulatus (Bath) is a methanotroph that possesses both a membrane-embedded (pMMO) and a soluble methane monooxygenase (sMMO). The expression of these two MMO's is tightly controlled by the availability of copper in the growth medium, but the underlying mechanisms and the number of genes involved in this switch in methane oxidation is not yet fully elucidated. Microarray analyses ...
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ورودعنوان ژورنال:
- Microbiology
دوره 142 ( Pt 5) شماره
صفحات -
تاریخ انتشار 1996