痢疾志贺氏菌1型产生的志贺毒素通过使氨酰tRNA结合失活来抑制网织红细胞裂解物中的蛋白质合成。

Shiga toxin from Shigella dysenteriae 1 inhibits protein synthesis in reticulocyte lysates by inactivation of aminoacyl-tRNA binding.

作者信息

Brown J E, Obrig T G, Ussery M A, Moran T P

机构信息

Department of Biological Chemistry, Walter Reed Army Institute of Research, Washington DC 20307-5100.

出版信息

Microb Pathog. 1986 Aug;1(4):325-34. doi: 10.1016/0882-4010(86)90065-3.

DOI:10.1016/0882-4010(86)90065-3

PMID:3334156

Abstract

Inhibition of the peptide elongation cycle of eukaryotic protein synthesis by Shiga toxin from Shigella dysenteriae 1 was examined in toxin-treated reticulocyte lysate mixtures. Peptidyl transferase activity of toxin-treated ribosomes was measured by following the decrease in peptidyl-tRNA concentrations when puromycin was added after incubation with toxin. Concentrations of [3H]leucine-labeled peptidyl-tRNA were measured by extraction with cetyltrimethylammonium bromide. The data suggest that Shiga toxin inhibited aminoacyl-tRNA binding. Toxin-treated ribosomes retained peptidyl transferase activity, and toxin did not block translocation. Furthermore, no inhibition of initiation of protein synthesis could be observed. Finally, Shiga toxin had no detectable nucleolytic effect on polysomal 28S rRNA, nor was hydrolysis of 5.8S or 5S rRNA observed.

摘要

在毒素处理的网织红细胞裂解物混合物中，检测了痢疾志贺氏菌1型的志贺毒素对真核生物蛋白质合成中肽链延伸循环的抑制作用。在用毒素孵育后加入嘌呤霉素时，通过跟踪肽基-tRNA浓度的降低来测量毒素处理的核糖体的肽基转移酶活性。用十六烷基三甲基溴化铵提取来测量[³H]亮氨酸标记的肽基-tRNA的浓度。数据表明志贺毒素抑制氨酰-tRNA的结合。毒素处理的核糖体保留了肽基转移酶活性，并且毒素没有阻断转位。此外，未观察到对蛋白质合成起始的抑制作用。最后，志贺毒素对多核糖体28S rRNA没有可检测到的核酸酶作用，也未观察到5.8S或5S rRNA的水解。