title: Detergent-labile, supramolecular assemblies of KcsA: relative abundance and interactions involved.
abstract: In this work, we illustrate the ability of the prokaryotic potassium channel KcsA to assemble into a variety of supramolecular clusters of defined sizes containing the tetrameric KcsA as the repeating unit. Such clusters, particularly the larger ones, are markedly detergent-labile and thus, disassemble readily upon exposure to the detergents commonly used in protein purification or conventional electrophoresis analysis. This is a reversible process, as cluster re-assembly occurs upon detergent removal and without the need of added membrane lipids. Interestingly, the dimeric ensemble between two tetrameric KcsA molecules are quite resistant to detergent disassembly to individual KcsA tetramers and along with the latter, are likely the basic building blocks through which the larger clusters are organized. As to the proteins domains involved in clustering, we have observed disassembly of KcsA clusters by SDS-like alkyl sulfates. As these amphiphiles bind to inter-subunit, "non-annular" sites on the protein, these observations suggest that such sites also mediate channel-channel interactions leading to cluster assembly.
authors.affiliation: Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche, 03202 Alicante, Spain.
authors.forename: A Marcela
authors.initials: AM
authors.lastname: Giudici
authors.forename: M Luisa
authors.initials: ML
authors.lastname: Molina
authors.forename: José L
authors.initials: JL
authors.lastname: Ayala
authors.forename: Estefanía
authors.initials: E
authors.lastname: Montoya
authors.forename: M Lourdes
authors.initials: ML
authors.lastname: Renart
authors.forename: Asia M
authors.initials: AM
authors.lastname: Fernández
authors.forename: José A
authors.initials: JA
authors.lastname: Encinar
authors.forename: Antonio V
authors.initials: AV
authors.lastname: Ferrer-Montiel
authors.forename: José A
authors.initials: JA
authors.lastname: Poveda
authors.forename: José M
authors.initials: JM
authors.lastname: González-Ros
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000737:chemistry; D003902:Detergents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004586:Electrophoresis / Q000379:methods; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel; D008055:Lipids / Q000737:chemistry; D008958:Models, Molecular; D015221:Potassium Channels / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary
chemical_list: D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D003902:Detergents; D008055:Lipids; D015221:Potassium Channels; C107790:prokaryotic potassium channel