Reconstitution of the mitochondrial ATP-dependent potassium channel into bilayer lipid membrane

• Published in: Journal of bioenergetics and biomembranes Vol. 31; no. 2; pp. 159 - 163
• Main Authors: Mironova, G D, Skarga, Y Y, Grigoriev, S M, Negoda, A E, Kolomytkin, O V, Marinov, B S
• Format: Journal Article
• Language: English
• Published: United States 01.04.1999
• Subjects: Adenosine Triphosphate - pharmacology; Adenosine Triphosphate - physiology; Animals; Intracellular Membranes - physiology; Lipid Bilayers; Male; Membrane Potentials - drug effects; Membrane Potentials - physiology; Mitochondria, Liver - physiology; Potassium - physiology; Potassium Channels - isolation & purification; Potassium Channels - physiology; Potassium Chloride - pharmacology; Rats; Rats, Wistar; Seasons; Substrate Specificity
• ISSN: 0145-479X
• DOI: 10.1023/A:1005408029549

Electrical properties and regulation of the mitochondrial ATP-dependent potassium channel were studied. The channel protein was solubilized from the mitochondrial membrane using an ethanol/water mixture. Reconstituted into a bilayer lipid membrane BLM), the protein formed a slightly voltage-dependent channel with a conductance of 10 pS in 100 mM KCl. Often, several channels worked simultaneously (clusters) when many channels were incorporated into the BLM. The elementary channel and the clusters were both highly potassium selective. At concentrations of 1 to 10 microM, ATP favors channel opening, while channels become closed at 1-3 mM ATP. GDP (0.5 mM) reactivated the ATP-closed channels without affecting the untreated channels. The sulfhydryl-reducing agent ditiothreitol increased the open probability at concentrations of 1 to 3 mM, but damaged the selectivity of the channel.