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The oxidation of methylamine in Paracoccus denitrificans
J W De Gier1, J Van der Oost, N Harms
1Department of Microbiology, BioCentrum Amsterdam, Vrije Universiteit, The Netherlands.
Abstract:
The in vivo oxidation of methylamine has been studied in Paracoccus denitrificans. Four components are involved in the electron transfer from methylamine to oxygen; methylamine dehydrogenase (MADH), amicyanin, cytochrome c and cytochrome-c oxidase. In P. denitrificans, MADH and its electron acceptor amicyanin are indispensable for growth on methylamine. In the present study, site-directed mutants have been used to demonstrate participation of cytochrome c550 and the aa3-type cytochrome-c oxidase. Moreover, evidence is provided for the operation of alternative routes, branching from amicyanin, in which at least cytochrome c1 and the cbb3-type cytochrome-c oxidase are involved.
Insights
Paracoccus denitrificans uses methylamine dehydrogenase (MADH) and amicyanin for methylamine oxidation. Alternative electron transfer routes involving cytochromes and oxidases were also identified.
Area of Science:
- Microbiology
- Biochemistry
- Electron Transport
Background:
- Methylamine oxidation is crucial for energy production in some bacteria.
- Paracoccus denitrificans utilizes a specific electron transport chain for methylamine metabolism.
Purpose of the Study:
- To elucidate the complete electron transfer pathway for methylamine oxidation in Paracoccus denitrificans.
- To identify the specific components and alternative routes involved in methylamine metabolism.
Main Methods:
- Site-directed mutagenesis was employed to generate mutants of Paracoccus denitrificans.
- The function of specific proteins in the electron transfer chain was investigated using these mutants.
Main Results:
- Methylamine dehydrogenase (MADH) and amicyanin are essential for growth on methylamine.
- Cytochrome c550 and the aa3-type cytochrome-c oxidase participate in the primary electron transfer pathway.
- Alternative electron transfer routes involving cytochrome c1 and the cbb3-type cytochrome-c oxidase were identified branching from amicyanin.
Conclusions:
- The study confirms the indispensable roles of MADH and amicyanin in methylamine utilization.
- Multiple electron transfer pathways, including alternative routes, contribute to methylamine oxidation in Paracoccus denitrificans, highlighting metabolic flexibility.