The Long Unwinding Road of RNA Helicases Franziska Bleichert, Susan J. Baserga  Molecular Cell  Volume 27, Issue 3, Pages 339-352 (August 2007) DOI: 10.1016/j.molcel.2007.07.014 Copyright © 2007 Elsevier Inc. Terms and Conditions

Figure 1 Conserved Sequence Motifs of DExD/H RNA Helicases and Their Functions Motif II (Walker B) contains the amino acids DEAD in DEAD box RNA helicases. The Q motif is specific to the family of DEAD box proteins. Molecular Cell 2007 27, 339-352DOI: (10.1016/j.molcel.2007.07.014) Copyright © 2007 Elsevier Inc. Terms and Conditions

Figure 2 RNA Helicases in Pre-mRNA Splicing and Schematic of the Pre-mRNA Splicing Cycle The RNA helicases involved in the different steps are indicated. Yeast Sub2 corresponds to UAP56 in humans. Ded1, another RNA helicase that has recently been indicated to associate with the spliceosome, has been omitted as it is not clear at which steps it functions. 5′SS, 5′ splice site; BP, branchpoint; and 3′SS, 3′ splice site. Molecular Cell 2007 27, 339-352DOI: (10.1016/j.molcel.2007.07.014) Copyright © 2007 Elsevier Inc. Terms and Conditions

Figure 3 RNA Helicases Involved in Eukaryotic Ribosome Biogenesis Simplified schematic of pre-rRNA processing for small (18S; left side) and large subunit rRNA (5.8S, 25S; right side) maturation with indicated cleavage sites. The 18S, 5.8S, and 25S rRNAs are transcribed as a polycistronic precursor. Several endo- and exonucleolytic cleavage steps occur in order to mature the rRNAs. RNA helicases involved in 18S maturation are indicated in red, those involved in 5.8S and 25S maturation are indicated in green, and RNA helicases that have been implicated to function in biogenesis of both small and large ribosomal subunits or are associated with SSU and LSU pre-rRNPs are represented in yellow. Esf2, the only known and characterized cofactor of a ribosome biogenesis RNA helicase, is indicated in blue. Please note that the cleavages at A0, A1, and A2 are only essential for SSU, but not for LSU biogenesis. ETS, external transcribed spacer; ITS, internal transcribed spacer. Molecular Cell 2007 27, 339-352DOI: (10.1016/j.molcel.2007.07.014) Copyright © 2007 Elsevier Inc. Terms and Conditions

Figure 4 Crystal Structures of the DEAD Box RNA Helicase Cores (A) Crystal structure of Drosophila Vasa in complex with poly(U) RNA (green) and the nonhydrolyzable ATP analog AMP-PNP (red). Both helicase domains (domain 1 and 2) are in a closed conformation, forming a narrow inderdomain cleft (based on Sengoku et al. [2006]). (B) Crystal structure of yeast eIF4A. Both RNA helicase domains are separated by a long flexible linker, resulting in a dumbbell-like structure and an open conformation (based on Caruthers et al. [2000]). Atomic coordinates were retrieved from the PDB database (accession numbers 2DB3 and 1FUU, respectively), and the models have been generated with UCSF Chimera (http://www.cgl.ucsf.edu/chimera; Pettersen et al., 2004). Molecular Cell 2007 27, 339-352DOI: (10.1016/j.molcel.2007.07.014) Copyright © 2007 Elsevier Inc. Terms and Conditions