Kretz O, Creppy E E, Dirheimer G
Institut de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Strasbourg, France.
Toxicology. 1991 Feb;66(2):213-24. doi: 10.1016/0300-483x(91)90220-u.
Protein, DNA, and RNA syntheses were assayed in Madin Darby canine kidney cells (MDCK) treated by bolestaine, a toxic glycoprotein from the mushroom Boletus satanas (single chain, Mr 63,000 +/- 3000, pI 8.3 +/- 0.1, disulphide intrachain bridge) previously shown to be an inhibitor of in vitro protein synthesis. Cellular protein and DNA syntheses are inhibited in a dose-dependent manner after 24 h of incubation, whereas the uptake of the labelled precursors of proteins, DNA and RNA biosyntheses into the cells is not affected. The IC50 of bolesatine for protein synthesis is 0.14 microM in the cell culture medium. RNA synthesis is not inhibited at this concentration. The IC50 for DNA synthesis is 0.32 microM. When galactose is added to the culture medium, it decreases or even abolishes the toxic effects, indicating that it prevents the toxin from binding on the membrane and penetrating inside the cells. The profiles of polysomes in MDCK cells treated with bolesatine, compared to the untreated ones, show an increasing pool of polysomes indicating that the toxin acts on the peptidyl elongation step in the protein synthesis.
在经鬼笔环肽处理的马-达二氏犬肾细胞（MDCK）中检测了蛋白质、DNA和RNA的合成。鬼笔环肽是一种来自撒旦牛肝菌的有毒糖蛋白（单链，分子量63,000±3000，等电点8.3±0.1，链内二硫键桥），先前已证明它是体外蛋白质合成的抑制剂。孵育24小时后，细胞蛋白质和DNA合成呈剂量依赖性受到抑制，而蛋白质、DNA和RNA生物合成的标记前体进入细胞的摄取不受影响。在细胞培养基中，鬼笔环肽对蛋白质合成的半数抑制浓度（IC50）为0.14微摩尔。在此浓度下RNA合成未受抑制。DNA合成的IC50为0.32微摩尔。当向培养基中添加半乳糖时，它会降低甚至消除毒性作用，这表明它可防止毒素与膜结合并穿透细胞内部。与未处理的MDCK细胞相比，经鬼笔环肽处理的MDCK细胞中的多核糖体图谱显示多核糖体池增加，这表明该毒素作用于蛋白质合成中的肽基延伸步骤。
