ATP-dependent DEAD-box helicases constitute one of the largest families of RNA helicases and are important regulators of most RNA-dependent cellular processes. The functional core of these enzymes consists of two RecA-like domains. Changes in the interdomain orientation of these domains upon ATP and RNA binding result in the unwinding of double-stranded RNA. The DEAD-box helicase DbpA from E. coli is involved in ribosome maturation. It possesses a C-terminal RNA recognition motif (RRM) in addition to the canonical RecA-like domains. The RRM recruits DbpA to nascent ribosomes by binding to hairpin 92 of the 23S rRNA. To follow the conformational changes of Dbpa during the catalytic cycle we initiated solution state NMR studies. We use a divide and conquer approach to obtain an almost complete resonance assignment of the isoleucine, leucine, valine, methionine and alanine methyl group signals of full length DbpA (49 kDa). In addition, we also report the backbone resonance assignments of two fragments of DbpA that were used in the course of the methyl group assignment. These assignments are the first step towards a better understanding of the molecular mechanism behind the ATP-dependent RNA unwinding process catalyzed by DEAD-box helicases.

依赖 ATP 的死盒解旋酶构成了最大的 RNA 解旋酶家族之一，并且是大多数依赖 RNA 的细胞过程的重要调节剂。这些酶的功能核心由两个 RecA 样结构域组成。这些结构域在 ATP 和 RNA 结合后的结构域间方向的变化导致双链 RNA 的解旋。来自大肠杆菌的 DEAD-box 解旋酶 DbpA参与核糖体成熟。除了典型的 RecA 样结构域外，它还具有 C 端 RNA 识别基序 (RRM)。RRM 通过与 23S rRNA 的发夹 92 结合，将 DbpA 招募到新生核糖体。为了跟踪催化循环期间 Dbpa 的构象变化，我们启动了溶液状态 NMR 研究。我们使用分而治之的方法来获得全长 DbpA (49 kDa) 的异亮氨酸、亮氨酸、缬氨酸、甲硫氨酸和丙氨酸甲基组信号的几乎完整的共振分配。此外，我们还报告了在甲基分配过程中使用的两个 DbpA 片段的骨架共振分配。这些分配是更好地理解由 DEAD-box 解旋酶催化的 ATP 依赖性 RNA 解旋过程背后的分子机制的第一步。