Kamyar Majidreza, Rawnduzi Pakiza, Studenik Christian R, Kouri Katerina, Lemmens-Gruber Rosa
Department of Pharmacology and Toxicology, University of Vienna, Althanstr. 14, A-1090 Vienna, Austria.
Arch Biochem Biophys. 2004 Sep 15;429(2):215-23. doi: 10.1016/j.abb.2004.06.013.
Enniatins are cyclohexadepsipeptides produced by various species of the genus Fusarium, and are known to have ionophoric, antibiotic, and in vitro hypolipidaemic properties. With the patch clamp technique in the inside-out mode it could be shown that enniatin easily incorporates into the cell membrane in which it forms cation-selective pores. This feature is characterized by unitary transitions to conductance levels typical for channels, ion selectivity, rectification, conductivity in the pS range, and block. A model of vertically stacked enniatin molecules that form sandwich complexes is suggested. Like gramicidin enniatin is a passive channel. Single channel properties for the isomers enniatin A1, B, and B1 differed from each other. This implies an influence of the substituted moieties on the complexation of cations. Electrical activity was followed by changes in intracellular ion concentrations, which are consistent with depolarization of the membrane resting potential, shortening of action potential duration, and reduced contractility.
恩镰孢菌素是由镰刀菌属的多种菌种产生的环六肽缩酚酸肽，已知具有离子载体、抗生素和体外降血脂特性。采用内面向外模式的膜片钳技术可以证明，恩镰孢菌素很容易整合到细胞膜中，并在其中形成阳离子选择性孔道。这一特性的特点是向通道典型的电导水平发生单一转变、离子选择性、整流、皮安范围内的电导率以及阻断。有人提出了一个形成三明治复合物的垂直堆叠恩镰孢菌素分子模型。与短杆菌肽一样，恩镰孢菌素是一种被动通道。异构体恩镰孢菌素A1、B和B1的单通道特性彼此不同。这意味着取代基团对阳离子络合有影响。电活动之后是细胞内离子浓度的变化，这与膜静息电位的去极化、动作电位持续时间的缩短以及收缩性降低是一致的。
