Vanzo N F, Li Y S, Py B, Blum E, Higgins C F, Raynal L C, Krisch H M, Carpousis A J
Laboratoire de Microbiologie et Génétique Moléculaire, UPR 9007, Centre National de la Recherche Scientifique (CNRS), 31062 Toulouse Cedex, France.
Genes Dev. 1998 Sep 1;12(17):2770-81. doi: 10.1101/gad.12.17.2770.
The Escherichia coli RNA degradosome is the prototype of a recently discovered family of multiprotein machines involved in the processing and degradation of RNA. The interactions between the various protein components of the RNA degradosome were investigated by Far Western blotting, the yeast two-hybrid assay, and coimmunopurification experiments. Our results demonstrate that the carboxy-terminal half (CTH) of ribonuclease E (RNase E) contains the binding sites for the three other major degradosomal components, the DEAD-box RNA helicase RhlB, enolase, and polynucleotide phosphorylase (PNPase). The CTH of RNase E acts as the scaffold of the complex upon which the other degradosomal components are assembled. Regions for oligomerization were detected in the amino-terminal and central regions of RNase E. Furthermore, polypeptides derived from the highly charged region of RNase E, containing the RhlB binding site, stimulate RhlB activity at least 15-fold, saturating at one polypeptide per RhlB molecule. A model for the regulation of the RhlB RNA helicase activity is presented. The description of RNase E now emerging is that of a remarkably complex multidomain protein containing an amino-terminal catalytic domain, a central RNA-binding domain, and carboxy-terminal binding sites for the other major components of the RNA degradosome.
大肠杆菌RNA降解体是最近发现的参与RNA加工和降解的多蛋白机器家族的原型。通过Far Western印迹法、酵母双杂交试验和共免疫纯化实验研究了RNA降解体各种蛋白质成分之间的相互作用。我们的结果表明，核糖核酸酶E（RNase E）的羧基末端半段（CTH）包含其他三个主要降解体成分的结合位点，即DEAD盒RNA解旋酶RhlB、烯醇化酶和多核苷酸磷酸化酶（PNPase）。RNase E的CTH充当复合物的支架，其他降解体成分在其上组装。在RNase E的氨基末端和中央区域检测到寡聚化区域。此外，源自RNase E高电荷区域的多肽，包含RhlB结合位点，可将RhlB活性刺激至少15倍，每个RhlB分子一个多肽时达到饱和。提出了RhlB RNA解旋酶活性调节模型。现在出现的关于RNase E的描述是一种非常复杂的多结构域蛋白，包含一个氨基末端催化结构域、一个中央RNA结合结构域以及RNA降解体其他主要成分的羧基末端结合位点。
