Obrig T G, Moran T P, Colinas R J
Biochem Biophys Res Commun. 1985 Jul 31;130(2):879-84. doi: 10.1016/0006-291x(85)90498-x.
All purified preparations of the ribosome-inactivating proteins ricin A, phytolaccin and Shiga toxin were shown to exhibit ribonuclease activity with 5S or 5.8S rRNA substrates. These toxin species generated reproducible patterns of RNA fragments distinct for each toxin species while multiple preparations of a single toxin species yielded similar RNA fragment patterns. The heat inactivation profile of Shiga toxin was identical for its RNase and protein synthesis inhibitory activities. These data are the first to indicate that the ribosome-inactivating catalytic toxins, in addition to alpha-sarcin, exhibit RNase activity. These results suggest RNase activity may be responsible for ribosome-inactivation catalyzed by ricin, phytolaccin and Shiga toxin proteins.
所有纯化的核糖体失活蛋白蓖麻毒素A、商陆素和志贺毒素制剂均显示对5S或5.8S rRNA底物具有核糖核酸酶活性。这些毒素种类产生了每种毒素特有的可重复的RNA片段模式，而单一毒素种类的多种制剂产生了相似的RNA片段模式。志贺毒素的热失活曲线对于其核糖核酸酶和蛋白质合成抑制活性是相同的。这些数据首次表明，除α-肌动蛋白外，核糖体失活催化毒素也具有核糖核酸酶活性。这些结果表明核糖核酸酶活性可能是由蓖麻毒素、商陆素和志贺毒素蛋白催化的核糖体失活的原因。
