Department of Natural Sciences, Hawaii Pacific University, Kaneohe, HI 96744, USA.
Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo, Hilo, HI 96720, USA.
Molecules. 2020 Feb 17;25(4):883. doi: 10.3390/molecules25040883.
Cubozoan nematocyst venoms contain known cytolytic and hemolytic proteins, but small molecule components have not been previously reported from cubozoan venom. We screened nematocyst extracts of and by LC-MS for the presence of small molecule metabolites. Three isomeric compounds, cnidarins 4A (), 4B (), and 4C (), were isolated from venom extracts and characterized by NMR and MS, which revealed their planar structure as cyclic γ-linked tetraglutamic acids. The full configurational assignments were established by syntheses of all six possible stereoisomers, comparison of spectral data and optical rotations, and stereochemical analysis of derivatized degradation products. Compounds - were subsequently detected by LC-MS in tissues of eight other cnidarian species. The most abundant of these compounds, cnidarin 4A (), showed no mammalian cell toxicity or hemolytic activity, which may suggest a role for these cyclic tetraglutamates in nematocyst discharge.
箱形水母刺丝囊毒液含有已知的细胞毒性和溶血蛋白，但以前从未从箱形水母毒液中报道过小分子成分。我们通过 LC-MS 对 和 的刺丝囊提取物进行筛选，以检测小分子代谢物的存在。从毒液提取物中分离出三种同分异构体化合物，cnidarins 4A()、4B()和 4C()，并通过 NMR 和 MS 进行了表征，揭示了它们作为环状γ-连接的四谷氨酸的平面结构。通过对所有六种可能的立体异构体进行合成、光谱数据和旋光的比较以及衍生降解产物的立体化学分析，确定了全构型的分配。在其他 8 种刺胞动物物种的组织中，通过 LC-MS 检测到了化合物 -。这些化合物中最丰富的是 cnidarin 4A()，它对哺乳动物细胞没有毒性或溶血活性，这可能表明这些环状四谷氨酸在刺丝囊放电中起作用。
