Leippe M, Andrä J, Nickel R, Tannich E, Müller-Eberhard H J
Department of Molecular Biology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Mol Microbiol. 1994 Dec;14(5):895-904. doi: 10.1111/j.1365-2958.1994.tb01325.x.
Three peptides with pore-forming activity were isolated from the cytoplasmic granules of pathogenic Entamoeba histolytica by acidic extraction, gel filtration and reversed-phase high-performance liquid chromatography. Partial amino acid sequence analysis of the three active peptides revealed that the most abundant of them was amoebapore and the other two were isoforms thereof. Cloning and sequencing of genomic DNA resolved the amino acid sequence of the two newly recognized peptides. The three peptides designated amoebapores A, B and C were found to have the same molecular size but to differ markedly in their primary structure, although all six cysteine residues are conserved. Despite sequence divergence, structural implications predict for the three peptides a similar amphipathic alpha-helical conformation stabilized by disulphide bonds. All three isoforms exhibit pore-forming activity toward lipid vesicles, but they differ in their kinetics. They also are capable of perturbing the integrity of bacterial cytoplasmic membranes and thereby kill Gram-positive bacteria. The amoebapores represent a distinct family of membrane-active peptides that may function intracellularly as antimicrobial agents but may also confer cytolytic activity on the parasite.
通过酸性提取、凝胶过滤和反相高效液相色谱法，从致病性溶组织内阿米巴的细胞质颗粒中分离出三种具有成孔活性的肽。对这三种活性肽的部分氨基酸序列分析表明，其中含量最丰富的是溶组织内阿米巴穿孔素，另外两种是其异构体。基因组DNA的克隆和测序解析了这两种新识别肽的氨基酸序列。发现这三种命名为溶组织内阿米巴穿孔素A、B和C的肽具有相同的分子大小，但一级结构明显不同，尽管所有六个半胱氨酸残基都是保守的。尽管序列存在差异，但结构分析预测这三种肽具有相似的由二硫键稳定的两亲性α-螺旋构象。所有三种异构体都对脂质囊泡表现出成孔活性，但它们的动力学不同。它们还能够破坏细菌细胞质膜的完整性，从而杀死革兰氏阳性细菌。溶组织内阿米巴穿孔素代表了一类独特的膜活性肽家族，它们可能在细胞内作为抗菌剂发挥作用，但也可能赋予寄生虫细胞溶解活性。
