Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Sciences, Suite 236 Rita Rossi Colwell Center, Baltimore, MD, 21202, USA.
Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL, 60612, USA.
Sci Rep. 2024 Aug 3;14(1):17998. doi: 10.1038/s41598-024-68669-0.
In 1957 Abbott and Ballantine described a highly toxic activity from a dinoflagellate isolated from the English Channel in 1949 by Mary Park. From a culture maintained at Plymouth Laboratory since 1950, we have been able to isolate two toxic molecules (abbotoxin and 59-E-Chloro-abbotoxin), determine the planar structures by analysis of HRMS and 1D and 2D NMR spectra, and found them to be karlotoxin (KmTx) congeners. Both toxins kill larval zebrafish with symptoms identical to those described by Abbot and Ballantine for gobies (Gobius virescens). Using surface plasma resonance the sterol binding specificity of karlotoxins is shown to require desmethyl sterols. Our results with black lipid membranes indicate that karlotoxin forms large-conductance channels in the lipid membrane, which are characterized by large ionic conductance, poor ionic selectivity, and a complex gating behavior that exhibits strong voltage dependence and multiple gating patterns. In addition, we show that KmTx 2 pore formation is a highly targeted mechanism involving sterol-specificity. This is the first report of the functional properties of the membrane pores formed by karlotoxins and is consistent with the initial observations of Abbott and Ballantine from 1957.
1957 年，雅培和巴兰坦（Abbott and Ballantine）描述了一种从玛丽·帕克（Mary Park）于 1949 年从英吉利海峡分离出的腰鞭毛藻中分离出的高毒性活性物质。自 1950 年以来，我们一直在普利茅斯实验室（Plymouth Laboratory）维持的培养物中，能够分离出两种有毒分子（阿博毒素和 59-E-氯阿博毒素），通过 HRMS 和 1D 和 2D NMR 光谱分析确定了它们的平面结构，并发现它们是卡洛夫毒素（Karlotoxin，KmTx）的同系物。这两种毒素都会杀死幼斑马鱼，其症状与雅培和巴兰坦（Abbott and Ballantine）描述的虾虎鱼（Gobius virescens）的症状完全相同。使用表面等离子体共振，我们发现卡洛夫毒素的固醇结合特异性需要去甲基固醇。我们用黑脂膜（black lipid membranes）的实验结果表明，卡洛夫毒素在脂膜中形成大电导通道，其特征是大离子电导率、差的离子选择性以及复杂的门控行为，表现出强烈的电压依赖性和多种门控模式。此外，我们还表明，KmTx2 孔的形成是一种高度靶向的机制，涉及固醇特异性。这是首次报道卡洛夫毒素形成的膜孔的功能特性，与雅培和巴兰坦（Abbott and Ballantine）1957 年的初步观察结果一致。
