Böddeker N, Stade K, Franceschi F
Max-Planck-Institut für Molekulare Genetik, AG Ribosomen, Ihnestrasse 73, 14195 Berlin, Germany.
Nucleic Acids Res. 1997 Feb 1;25(3):537-45. doi: 10.1093/nar/25.3.537.
DbpA is a putative Escherichia coli ATP dependent RNA helicase belonging to the family of DEAD box proteins. It hydrolyzes ATP in the presence of 23S ribosomal RNA and 93 bases in the peptidyl transferase center of 23S rRNA are sufficient to trigger 100% of the ATPase activity of DbpA. In the present study we characterized the ATPase and RNA unwinding activities of DbpA in more detail. We report that-in contrast to eIF-4A, the prototype of the DEAD box protein family-the ATPase and the helicase activities of DbpA are not coupled. Moreover, the RNA unwinding activity of DbpA is not specific for 23S rRNA, since DbpA is also able to unwind 16S rRNA hybrids. Furthermore, we determined that the ATPase activity of DbpA is triggered to a significant extent not only by the 93 bases of the 23S rRNA previously reported but also by other regions of the 23S rRNA molecule. Since all these regions of 23S rRNA are either part of the 'functional core' of the 50S ribosomal subunit or involved in the 50S assembly, DbpA may play an important role in the ribosomal assembly process.
DbpA是一种假定的大肠杆菌ATP依赖性RNA解旋酶，属于DEAD盒蛋白家族。它在23S核糖体RNA存在的情况下水解ATP，并且23S rRNA肽基转移酶中心的93个碱基足以触发DbpA 100%的ATP酶活性。在本研究中，我们更详细地表征了DbpA的ATP酶和RNA解旋活性。我们报告，与DEAD盒蛋白家族的原型eIF-4A相反，DbpA的ATP酶和解旋酶活性不相关联。此外，DbpA的RNA解旋活性并非对23S rRNA具有特异性，因为DbpA也能够解开16S rRNA杂交体。此外，我们确定，DbpA的ATP酶活性不仅在很大程度上由先前报道的23S rRNA的93个碱基触发，而且还由23S rRNA分子的其他区域触发。由于23S rRNA的所有这些区域要么是50S核糖体亚基“功能核心”的一部分，要么参与50S组装，因此DbpA可能在核糖体组装过程中发挥重要作用。
