Details

Autor(en) / Beteiligte

• Cava, Daniel G.
• Alvarez-Malmagro, Julia
• Natale, Paolo
• López-Calcerrada, Sandra
• López-Montero, Iván
• Ugalde, Cristina
• Abad, Jose Maria
• Pita, Marcos
• De Lacey, Antonio L.
• Vélez, Marisela

Titel

Electrochemical detection of quinone reduced by Complex I Complex II and Complex III in full mitochondrial membranes

Ist Teil von

• Electrochimica acta, 2024-04, Vol.484, p.144042, Article 144042

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2024

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •Pig heart mitochondrial membrane fragments can be deposited on functionalized gold electrodes.•The activity of Complex I, Complex II and Complex III can be monitored electrochemically measuring the reducing current of the electron mediator CoQ1 in the presence of their respective substrates using cyclic voltammetry.•Electrochemical detection of respiratory chain complexes in their native membrane reflected unexpected interactions between different complexes.•Mitochondrial-membrane modified electrodes could be used to develop high-throughput electrochemical sensors for screening respiratory chain protein activity in their native environment. In the last decades enormous advances have been made in characterizing the atomic and molecular structure of respiratory chain supercomplexes [1]. However, it still remains a challenge to stitch this refined spatial atomistic description with functional information provided by biochemical studies of isolated protein material. Development of functional assays that detect respiratory chain complexes in their native membrane environment contribute to address the open questions related to the role played by their association and interactions. We present a characterization assay in which a functionalized gold electrode is modified with mitochondrial membrane fragments that allows monitoring electrochemically the activity of different respiratory chain complexes immersed in the mitochondrial membrane. We measure the intensity of the reducing current of the electron mediator CoQ1 at the electrode surface and its variation upon addition of the corresponding enzymatic substrates. The activities of Complex I, Complex II and Complex III were monitored by the way in which they reduce the current, reflecting the amount of quinone reduced by the complexes in the presence of their substrates. We detect that CoQ1H2 produced by Complex I remains partially trapped within the membrane and is more easily oxidized by Complex III or the electrode than the quinone reduced by Complex II. [Display omitted]