Blepharismins, produced by the protozoan, Blepharisma japonicum, form ion‐permeable channels in planar lipid bilayer membranes

FEBS Letters

Muto, Yoshinori²  Kirino, Yutaka³  Kida, Akemi¹  Okano, Yukio⁴  Matsuoka, Tatsuomi¹ 

[1]Department of Natural Environmental Science, Faculty of Science, Kochi University, Kochi 780-8520, Japan

[2]Department of Basic Health Science and Fundamental Nursing, Gifu University School of Medicine, 1-1, Yanagido, Gifu 501-1193, Japan

[3]Laboratory of Neurobiophysics, School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan

[4]Department of Molecular Pathobiochemistry, Gifu University School of Medicine, Gifu 500-8705, Japan

关键词: Blepharismin;    Ion channel;    Planar lipid bilayer;    Cytotoxicity;    Protozoon;   

DOI  :  10.1016/S0014-5793(01)03110-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Blepharismins are polycyclic quinones found in the pigment granules of the ciliated protozoan, Blepharisma. Exposure to purified blepharismins results in lethal damage to several other ciliates. We here report that, at cytotoxic concentrations, blepharismins formed cation-selective channels in planar phospholipid bilayer membranes. The channels formed in a diphytanoylphosphatidylcholine bilayer had a K⁺/Cl⁻ permeability ratio of 6.6:1. Single channel recordings revealed the conductance to be quite heterogeneous, ranging from 0.2 to 2.8 nS in solutions containing 0.1 M KCl, possibly reflecting different states of aggregation of blepharismin. Our observations suggest that channel formation is a cytotoxic mechanism of blepharismin's action against predatory protozoa.

【 授权许可】

Unknown