Tauchert, Marcel J.Marcel J.TauchertFourmann, Jean-BaptisteJean-BaptisteFourmannLührmann, ReinhardReinhardLührmannFicner, RalfRalfFicner2017-03-022021-10-272017-03-022021-10-272017https://resolver.sub.uni-goettingen.de/purl?gro-2/91831The DEAH-box helicase Prp43 is a key player in pre-mRNA splicing as well as the maturation of rRNAs. The exact modus operandi of Prp43 and of all other spliceosomal DEAH-box RNA helicases is still elusive. Here, we report crystal structures of Prp43 complexes in different functional states and the analysis of structure-based mutants providing insights into the unwinding and loading mechanism of RNAs. The Prp43.ATP-analog.RNA complex shows the localization of the RNA inside a tunnel formed by the two RecA-like and C-terminal domains. In the ATP-bound state this tunnel can be transformed into a groove prone for RNA binding by large rearrangements of the C-terminal domains. Several conformational changes between the ATP- and ADP-bound states explain the coupling of ATP hydrolysis to RNA translocation, mainly mediated by a b-turn of the RecA1 domain containing the newly identified RF motif. This mechanism is clearly different to those of other RNA helicases.enCC BY 4.0https://creativecommons.org/licenses/by/4.0journal_article10.7554/eLife.21510280922613142192https://resolver.sub.uni-goettingen.de/purl?gs-1/14343