Taghbalout Aziz, Rothfield Lawrence
Department of Molecular, Microbial, and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut 06032, USA.
J Biol Chem. 2008 May 16;283(20):13850-5. doi: 10.1074/jbc.M709118200. Epub 2008 Mar 12.
The RNA degradosome of Escherichia coli is a multiprotein complex that plays an essential role in normal RNA processing and decay. It was recently shown that the major degradosome constituents are organized in a coiled cytoskeletal-like structure that extends along the length of the cell. Here we show that the endoribonuclease E (RNaseE) and RNA helicase B (RhlB) components of the degradosome can each independently form coiled structures in the absence of the other degradosome proteins. In contrast, the cytoskeletal organization of the other degradosome proteins required the presence of the RNaseE or RhlB coiled elements. Although the RNaseE and RhlB structures were equally competent to support the helical organization of polynucleotide phosphorylase, the cytoskeletal-like organization of enolase occurred only in the presence of the RNaseE coiled structure. The results indicate that the RNA degradosome proteins are components of the bacterial cytoskeleton rather than existing as randomly distributed multiprotein complexes within the cell and suggest a model for the cellular organization of the components within the helical degradosomal structure.
大肠杆菌的RNA降解体是一种多蛋白复合体，在正常RNA加工和降解过程中发挥着重要作用。最近研究表明，主要的降解体成分以一种类似细胞骨架的螺旋结构形式排列，该结构沿细胞长度延伸。在此，我们发现，在没有其他降解体蛋白的情况下，降解体的核糖核酸酶E（RNaseE）和RNA解旋酶B（RhlB）成分各自都能独立形成螺旋结构。相比之下，其他降解体蛋白的细胞骨架组织需要RNaseE或RhlB螺旋元件的存在。尽管RNaseE和RhlB结构同样能够支持多核苷酸磷酸化酶的螺旋组织，但烯醇化酶的类似细胞骨架的组织仅在存在RNaseE螺旋结构时才会出现。结果表明，RNA降解体蛋白是细菌细胞骨架的组成成分，而非作为细胞内随机分布的多蛋白复合体存在，并提出了一种关于螺旋状降解体结构内各成分细胞组织的模型。
