产气荚膜梭菌iota毒素和肉毒梭菌C2毒素对肌动蛋白的去ADP核糖基化作用。
De-ADP-ribosylation actin by Clostridium perfringens iota-toxin and Clostridium botulinum C2 toxin.
作者信息
Just I, Geipel U, Wegner A, Aktories K
机构信息
Pharmakologisches Institut, Universitätsklinikums Essen, Federal Republic of Germany.
出版信息
Eur J Biochem. 1990 Sep 24;192(3):723-7. doi: 10.1111/j.1432-1033.1990.tb19282.x.
The reverse reaction of the ADP-ribosylation of actin by Clostridium botulinum C2 toxin and Clostridium perfringens iota-toxin was studied. In the presence of nicotinamide (30-50 mM) C2 toxin and iota-toxin decreased the radioactive labeling of [32P]ADP-ribosylated actin and catalyzed the formation of [32P]NAD. The pH optima for both reactions were 5.5-6.0. Concomitant with the removal of ADP-ribose, the ability of actin to polymerize was restored and actin ATPase activity increased. Neither ADP-ribosylation nor removal of ADP-ribose was observed after treatment of actin with EDTA, indicating that the native structure of actin is required for both reactions. ADP-ribosylation of platelet actin by C2 toxin was reversed by iota-toxin, confirming recent reports that both toxins modify the same amino acid in actin. However, C. botulinum C2 toxin was not able to cleave ADP-ribose from skeletal muscle actin which had been incorporated by iota-toxin, corroborating the different substrate specificities of both toxins.
研究了肉毒梭菌C2毒素和产气荚膜梭菌iota毒素对肌动蛋白进行ADP核糖基化的逆反应。在烟酰胺（30 - 50 mM）存在的情况下，C2毒素和iota毒素降低了[32P]ADP核糖基化肌动蛋白的放射性标记，并催化了[32P]NAD的形成。两个反应的最适pH均为5.5 - 6.0。伴随着ADP核糖的去除，肌动蛋白聚合的能力得以恢复，且肌动蛋白ATP酶活性增加。用EDTA处理肌动蛋白后，未观察到ADP核糖基化或ADP核糖的去除，这表明两个反应都需要肌动蛋白的天然结构。iota毒素可逆转C2毒素对血小板肌动蛋白的ADP核糖基化，这证实了最近的报道，即两种毒素修饰肌动蛋白中的同一位氨基酸。然而，肉毒梭菌C2毒素无法从已被iota毒素掺入的骨骼肌肌动蛋白上裂解下ADP核糖，这证实了两种毒素不同的底物特异性。
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