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Exploring substrate interaction in respiratory alternative complex III from Rhodothermus marinus
Filipa Calisto1, Smilja Todorovic2, Ricardo O Louro2
1University of Lisbon, Faculty of Sciences, Department of Chemistry and Biochemistry and BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8, 1749-016 Lisboa, Portugal.
Biochimica Et Biophysica Acta. Bioenergetics
|May 1, 2023
Summary
Rhodothermus marinus possesses a unique Alternative Complex III (ACIII) for respiration at high temperatures. This study used nanodiscs to investigate ACIII
Area of Science:
- Microbiology
- Biochemistry
- Structural Biology
Background:
- Rhodothermus marinus is a thermohalophilic bacterium thriving at 65°C.
- Its microaerobic metabolism is optimized for extreme conditions.
- A novel quinone:cytochrome c oxidoreductase, Alternative Complex III (ACIII), distinct from the bc1 complex, has been identified.
Purpose of the Study:
- To investigate the activity and function of Alternative Complex III (ACIII) in a membrane-mimicking environment.
- To elucidate the interactions of ACIII with its substrates and electron acceptors.
Main Methods:
- Utilized nanodiscs and liposomes to create membrane-mimicking systems.
- Studied the enzymatic activity of ACIII in these reconstituted systems.
- Investigated the interaction of ACIII with menaquinone, HiPIP, cytochrome c, and the caa3 oxygen reductase.
Main Results:
- ACIII activity was successfully reconstituted and studied in nanodiscs and liposomes.
- The interaction of ACIII with menaquinone and its electron acceptors was characterized.
- The interplay between ACIII and the caa3 oxygen reductase was explored.
Conclusions:
- Alternative Complex III (ACIII) plays a significant role in the respiratory chain of Rhodothermus marinus.
- Membrane-mimicking systems are effective for studying ACIII function.
- Further research into ACIII provides insights into microbial adaptation to extreme environments.
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