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Updated: May 9, 2026

Isolation of Mitochondria for Mitochondrial Supercomplex Analysis from Small Tissue and Cell Culture Samples
Published on: May 3, 2024
The bc:caa3 supercomplexes from the Gram positive bacterium Bacillus subtilis respiratory chain: a megacomplex
Pedro M F Sousa1, Marco A M Videira, Filipe A S Santos
1BIOTROP, Instituto de Investigação Científica Tropical, R. da Junqueira, Lisboa, Portugal.
Abstract:
The respiratory chain of some prokaryotes was shown to be organized in supercomplexes. This association has been proposed to improve enzyme stability and the overall efficiency of the oxidative phosphorylation process. Here, we have revisited recent data on the supercomplexes of Bacillus subtilis respiratory chain, by means of 1D and 2D-BN-PAGE, sucrose gradient fractionation of solubilized membranes, and mass spectrometry analysis of BN-PAGE bands detected in gel for succinate and cytochrome c oxidoreductase activities. The cytochrome bc:caa3 oxygen oxidoreductase supercomplex was observed in different stoichiometries, (bc)4:(caa3)2, (bc)2:(caa3)4 and 2[(bc)2:(caa3)4], suggesting for the first time the string association model of supercomplexes in a Gram positive bacterium. In addition, the presence of a succinate:quinone oxidoreductase:nitrate reductase supercomplex was confirmed by the co-localized succinate:nitroblue tetrazolium and methylviologen:nitrate oxidoreductase activities detected in gel and corroborated by LC-MS/MS analysis.
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