Kiel M C, Aoki H, Ganoza M C
Banting and Best Department of Medical Research, University of Toronto, Ontario, Canad.
Biochimie. 1999 Dec;81(12):1097-108. doi: 10.1016/s0300-9084(99)00352-1.
Eukaryotic ribosomes harbor an ATPase activity that has been shown to be essential for translation elongation in some lower fungi. Here we report the first identification of a ribosome bound ATPase, RbbA, in E. coli cells. RbbA accounts for most of the ATPase activity associated with 70S ribosomes and 30S ribosomal subunits. Both native and recombinant RbbA were purified and shown to possess ribosome-dependent ATPase activities and to stimulate polyphenylalanine synthesis in vitro. Biochemically, RbbA is similar to the fungi-specific translation elongation factor 3 (EF-3) and cross-reacts with antibody raised against EF-3. The gene encoding RbbA is identified as ORF yhih and the predicted RbbA amino acid sequence is 40% similar to that of the C-terminal half of EF-3. The discovery of a ribosomal ATPase in a prokaryotic cell suggests a common, conserved function for these proteins in translation.
真核生物核糖体具有一种ATP酶活性，已证明该活性在某些低等真菌的翻译延伸过程中至关重要。在此，我们报告首次在大肠杆菌细胞中鉴定出一种与核糖体结合的ATP酶RbbA。RbbA占与70S核糖体和30S核糖体亚基相关的大部分ATP酶活性。天然和重组的RbbA均被纯化，并显示具有核糖体依赖性ATP酶活性，且能在体外刺激聚苯丙氨酸的合成。从生化角度来看，RbbA与真菌特异性翻译延伸因子3（EF-3）相似，并能与针对EF-3产生的抗体发生交叉反应。编码RbbA的基因被鉴定为开放阅读框yhih，预测的RbbA氨基酸序列与EF-3 C端一半的序列有40%的相似性。在原核细胞中发现核糖体ATP酶表明这些蛋白质在翻译过程中具有共同的保守功能。
