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Abstract：
We demonstrated the hitherto unknown property of the mycotoxin sterigmatocystin (STC) to provide homogeneous solutions in aqueous medium by forming a unique aggregate type (not formed by analogous aflatoxins), characterized by exceptionally strong circular dichroism (CD) bands in the 300-400 nm range. Results showed that these CD bands do not originate from intrinsic STC chirality but are a specific property of a peculiar aggregation process similar to psi-DNA CD response. Transmission electron microscopy (TEM) experiments revealed a fine fiber network resembling a supramolecular gel structure with helical fibers. Thermodynamic studies of aggregates by differential scanning calorimetry (DSC) revealed high reversibility of the dominant aggregation process. We demonstrated that the novel STC psi-CD band at 345 nm could be applied at biorelevant conditions (100 nanomolar concentration) and even in marine-salt content conditions for specific and quantitative monitoring of STC. Also, we showed that STC strongly non-covalently interacts with ds-DNA with likely toxic effects, thus contrary to the previous belief requiring prior enzyme epoxidation.
摘要：
我们证明了霉菌毒素杂色霉素（STC）迄今为止未知的特性，可以通过形成独特的聚集体类型（不是由类似的黄曲霉毒素形成）在水性介质中提供均匀的溶液，其特征在于在300-400nm范围内异常强的圆二色性(CD)带。结果表明，这些CD带并非源自固有的STC手性，而是类似于psi-DNACD响应的特殊聚集过程的特定特性。透射电子显微镜（TEM）实验表明，细纤维网络类似于具有螺旋纤维的超分子凝胶结构。通过差示扫描量热法（DSC）对聚集体进行的热力学研究表明，主要聚集过程具有很高的可逆性。我们证明了在345nm处的新型STCpsi-CD带可以在生物相关条件（100纳摩尔浓度）下甚至在海洋盐含量条件下应用，以对STC进行特定和定量监测。此外，我们表明STC与DS-DNA强烈非共价相互作用，可能具有毒性作用，因此与以前的信念相反，需要事先进行酶环氧化。
