Mechanisms of activity of DEAD-box helicases studied by NMR: a dynamic view.
Final Report Abstract
In this work, we could demonstrate that ADP induces a conformational change of the D1 domain that is not compatible with RNA binding. The determination of the high-resolution structure of D1 in complex with ADP is underway. In addition, in the limit of the experimental errors and of the detection range of our measurements, we could demonstrate that Vasa135-564 is not present in a minor population of closed state in the absence of RNA. In the presence of RNA, Vasa135-564 forms a small percentage of a stable Vasa135-564–ATP–dsRNA particle. Hydrolysis of ATP to ADP causes this particle to disassemble, providing a rationale for the role of ATP hydrolysis in enzymatic turnover. In this project we had difficulties caused by the poor behavior of the perdeuterated protein as well as the low percentage of Vasa135-564–ATP–dsRNA complex present at concentrations as high as hundreds of micromolar.
