Influence of lipids on membrane assembly and stability of the potassium channel KcsA

FEBS Letters

van Dalen, Annemieke¹  Hegger, Sander¹  Killian, J.Antoinette¹  de Kruijff, Ben¹ 

[1]Department Biochemistry of Membranes, Centre for Biomembranes and Lipid Enzymology, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands

关键词: Lipid bilayer;    Membrane insertion;    Oligomerization;    Protein–lipid interaction;    Thermo-stability;    PC;    phosphatidylcholine;    PE;    phosphatidylethanolamine;    PG;    phosphatidylglycerol;    DDM;    n-dodecyl-β-D-maltoside;    IMV;    inverted Escherichia coli inner membrane vesicle;    LUV;    large unilamellar vesicle;    SRP;    signal recognition particle;    TLE;    total Escherichia coli lipid extract;    T m;    melting temperature;   

DOI  :  10.1016/S0014-5793(02)03061-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Recently we observed in an in vitro system that newly synthesized KcsA assembles efficiently into a tetramer in lipid vesicles [van Dalen et al. (2002) FEBS Lett. 511, 51–58]. Here we used this system to get insight into the importance of the lipid composition for KcsA membrane association and tetramerization and we compared this to the lipid dependency of the thermo-stability of the KcsA tetramer. It was found that a large amount of phosphatidylethanolamine (>40 mol%) and a lower amount of phosphatidylglycerol (∼20–30 mol%) were optimal for efficient KcsA membrane association and tetramerization. Strikingly, vesicles of the abundant and commonly used membrane lipid phosphatidylcholine did not support assembly, further demonstrating the importance of membrane lipid composition for KcsA assembly. The in vitro assembled KcsA tetramer showed similar thermo-stability in biological and pure lipid membranes, demonstrating that both tetramers are alike. In addition, we show that solubilization of the membrane with detergent reduces the thermo-stability of the tetramer. The highest KcsA tetramer stability was observed in intact bilayers in the presence of anionic lipids.

【 授权许可】

Unknown