Snook C F, Woolley G A, Oliva G, Pattabhi V, Wood S F, Blundell T L, Wallace B A
Department of Crystallography Birkbeck College University of London London, WC1E 7HX, UK.
Structure. 1998 Jun 15;6(6):783-92. doi: 10.1016/s0969-2126(98)00079-3.
Antiamoebin is a member of the peptaibol family of polypeptides and has a unique antibiotic activity: it acts as an antiamoebic agent, but does not effectively haemolyze erythrocytes even though it does exhibit membrane-modifying activity.
The structure of antiamoebin I has been determined by X-ray crystallography at 1.4 A resolution. The molecule forms a helical structure, which, as a result of the presence of a number of proline and hydroxyproline residues, has a deep bend in the middle. Circular dichroism spectroscopy, single-channel conductance studies and fluorescence diffusion studies suggest a mode of ion transport that is entirely different from that of the other two members of the peptaibol family (alamethicin and zervamicin) whose structures and functions have been examined in detail.
The structure of the polypeptide has been determined and a functional model for its mode of action in membranes is presented. Although under some conditions antiamoebin may form ion channels, unlike the closely related alamethicin and zervamicin polypeptides, its major membrane-modifying activity appears to be as an ion carrier.
抗阿米巴菌素是肽菌素家族多肽的成员，具有独特的抗菌活性：它作为一种抗阿米巴药物，但即使它确实表现出膜修饰活性，也不能有效地使红细胞溶血。
已通过X射线晶体学在1.4埃分辨率下确定了抗阿米巴菌素I的结构。该分子形成螺旋结构，由于存在许多脯氨酸和羟脯氨酸残基，在中间有一个深弯。圆二色光谱、单通道电导研究和荧光扩散研究表明，离子运输模式与肽菌素家族的其他两个成员（阿拉霉素和泽尔瓦霉素）完全不同，后两者的结构和功能已得到详细研究。
已确定该多肽的结构，并提出了其在膜中的作用模式的功能模型。尽管在某些条件下抗阿米巴菌素可能形成离子通道，但与密切相关的阿拉霉素和泽尔瓦霉素多肽不同，其主要的膜修饰活性似乎是作为离子载体。
