Interaction of ostreolysin, a cytolytic protein from the edible mushroom Pleurotus ostreatus, with lipid membranes and modulation by lysophospholipids
Interaction of ostreolysin, a cytolytic protein from the edible mushroom Pleurotus ostreatus, with lipid membranes and modulation by lysophospholipids
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DOI：
10.1046/j.1432-1033.2003.03480.x
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发表时间：
2003-03-01
期刊：
影响因子：
--
通讯作者：
Menestrina, G
中科院分区：
文献类型：
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作者：
Sepcic, K;Berne, S;Menestrina, G
平菇溶血素是一种16 kDa的细胞溶解蛋白，在食用菌平菇的原基和子实体中特异表达。为了了解它与脂膜的相互作用，我们比较了它对哺乳动物细胞、用纯脂或总脂提取物制备的囊泡以及对溶血磷脂或脂肪酸分散的影响。在纳摩尔浓度下，该蛋白以胶体渗透机制裂解人、牛和羊的红细胞，与直径为4 nm的孔的形成相容，对哺乳动物肿瘤细胞具有细胞毒作用。对溶血脂质抑制剂的研究发现，溶血磷脂和脂肪酸在临界胶束浓度以下有很强的作用。这一作用不同于Ostreolysin结合和渗透脂膜的能力。事实上，只有当囊泡是用从红细胞中提取的脂类制备的，而不是用从平菇或纯脂混合物中提取的脂类制备时，囊泡的透过性才会发生，即使包括溶血磷脂或脂肪酸。与脂泡的相互作用及其通透性与蛋白质的本征荧光和α-螺旋含量的增加以及聚集相关，而溶血磷脂没有检测到这一点。似乎需要未知的脂质受体或特定的脂类复合体来结合、聚集和形成毛孔。溶血磷脂的抑制作用可能反映了这些成分在果实形成过程中对溶血素及其相关蛋白的生理调节作用。
Ostreolysin is a 16-kDa cytolytic protein specifically expressed in primordia and fruiting bodies of the edible mushroom Pleurotus ostreatus . To understand its interaction with lipid membranes, we compared its effects on mammalian cells, on vesicles prepared with either pure lipids or total lipid extracts, and on dispersions of lysophospholipids or fatty acids. At nanomolar concentrations, the protein lysed human, bovine and sheep erythrocytes by a colloid-osmotic mechanism, compatible with the formation of pores of 4 nm diameter, and was cytotoxic to mammalian tumor cells. A search for lipid inhibitors of hemolysis revealed a strong effect of lysophospholipids and fatty acids, occurring below their critical micellar concentration. This effect was distinct from the capacity of ostreolysin to bind to and permeabilize lipid membranes. In fact, permeabilization of vesicles occurred only when they were prepared with lipids extracted from erythrocytes, and not with lipids extracted from P. ostreatus or pure lipid mixtures, even if lysophospholipids or fatty acids were included. Interaction with lipid vesicles, and their permeabilization, correlated with an increase in the intrinsic fluorescence and alpha-helical content of the protein, and with aggregation, which were not detected with lysophospholipids. It appears that either an unknown lipid acceptor or a specific lipid complex is required for binding, aggregation and pore formation. The inhibitory effect of lysophospholipids may reflect a regulatory role for these components on the physiological action of ostreolysin and related proteins during fruiting.