Oligomeric properties of .alpha.-dendrotoxin-sensitive potassium ion channels purified from bovine brain

• Published in: Biochemistry (Easton) 1992-11, Vol.31 (45), p.11084-11088
• Main Authors: Parcej, David N, Scott, Victoria E. S, Dolly, J. Oliver
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Brain - metabolism; Cattle; Cell physiology; Chromatography, Gel; Elapid Venoms - pharmacology; Electrophoresis, Polyacrylamide Gel; Fundamental and applied biological sciences. Psychology; Membrane and intracellular transports; Molecular and cellular biology; Neurotoxins - pharmacology; Potassium Channels - chemistry; Potassium Channels - drug effects
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi00160a018

Neuronal acceptors for alpha-dendrotoxin (alpha-DTX) have recently been purified from mammalian brain and shown to consist of two classes of subunit, a larger (approximately 78,000 M(r)) protein (alpha) whose N-terminal sequence is identical to that of a cloned, alpha-DTX-sensitive K+ channel, and a novel M(r) 39,000 (beta) polypeptide of unknown function. However, little information is available regarding the oligomeric composition of these native molecules. By sedimentation analysis of alpha-DTX acceptors isolated from bovine cortex, two species have been identified. A minority of these oligomers contain only the larger protein, while the vast majority possess both subunits. Based on accurate determination of the molecular weights of these two forms it is proposed that alpha-DTX-sensitive K+ channels exist as alpha 4 beta 4 complexes because this combination gives the best fit to the experimental data.