Related Experiment Videos
Particulate methane monooxygenase from Methylosinus trichosporium is a copper-containing enzyme
Jia-Ying Xin1, Jun-Ru Cui, Xiao-Xue Hu
1State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China. xinjy1966@hotmail.com
Abstract:
Particulate methane monooxygenase (pMMO) has been exfoliated and isolated from membranes of the Methylosinus trichosporium IMV 3011. It appears that the stability of pMMO in the exfoliation process is increased with increasing copper concentration in the growth medium, but extensive intracytoplasmic membrane formed under higher copper concentration may inhibit the exfoliation of active pMMO from membrane. The highest total activity of purified pMMO is obtained with an initial concentration of 6 microM Cu in the growth medium. The purified MMO contains only copper and does not utilize NADH as electron donor. Treatment of purified pMMO with EDTA resulted in little change in copper level, suggesting that the copper in the pMMO is tightly bound with pMMO.
Insights
Copper concentration impacts particulate methane monooxygenase (pMMO) stability and activity in Methylosinus trichosporium. Optimal purification occurs at 6 microM Cu, revealing tightly bound copper in active pMMO.
Area of Science:
- Biochemistry
- Microbiology
- Enzyme Purification
Background:
- Particulate methane monooxygenase (pMMO) is crucial for methane oxidation.
- Understanding pMMO's structure and function requires effective isolation techniques.
- Copper availability is known to influence pMMO expression and activity.
Purpose of the Study:
- To optimize the exfoliation and isolation of active pMMO from Methylosinus trichosporium IMV 3011.
- To investigate the effect of copper concentration on pMMO stability and activity during purification.
- To characterize the purified pMMO, focusing on its copper content and cofactor requirements.
Main Methods:
- Exfoliation and isolation of pMMO from Methylosinus trichosporium membranes.
- Cultivation of Methylosinus trichosporium with varying copper concentrations (0-6 microM Cu).
- Enzyme activity assays and biochemical characterization (EDTA treatment, cofactor analysis).
Main Results:
- pMMO stability increased with copper concentration, but high levels inhibited exfoliation.
- Optimal pMMO activity was achieved with 6 microM Cu in the growth medium.
- Purified pMMO contained only copper, did not use NADH, and showed tightly bound copper resistant to EDTA treatment.
Conclusions:
- Copper concentration is a critical factor for both pMMO activity and successful purification.
- The optimal copper level balances pMMO expression/activity with membrane properties for efficient isolation.
- The tightly bound copper is essential for pMMO's catalytic function.