The DEXD/H-box RNA helicase DDX19 is regulated by an {alpha}-helical switch - PubMed (original) (raw)

The DEXD/H-box RNA helicase DDX19 is regulated by an {alpha}-helical switch

Ruairi Collins et al. J Biol Chem. 2009.

Abstract

DEXD/H-box RNA helicases couple ATP hydrolysis to RNA remodeling by an unknown mechanism. We used x-ray crystallography and biochemical analysis of the human DEXD/H-box protein DDX19 to investigate its regulatory mechanism. The crystal structures of DDX19, in its RNA-bound prehydrolysis and free posthydrolysis state, reveal an alpha-helix that inserts between the conserved domains of the free protein to negatively regulate ATPase activity. This finding was corroborated by biochemical data that confirm an autoregulatory function of the N-terminal region of the protein. This is the first study describing crystal structures of a DEXD/H-box protein in its open and closed cleft conformations.

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Figures

FIGURE 1.

FIGURE 1.

Structure of human DDX19. A, overview of DDX19 with ADP bound and the N-terminal flanking helix in the central cleft. The Arg429 side chain that acts as an arginine finger is presented as_sticks. B_, schematic representation of the cleft-inserted helix with the two conserved domains of the protein, shown in the same view as in_panel A_. Residues that are conserved in DDX25 are shown in blue. C, overview of the DDX19-RNA complex, with Mg-ADPNP bound in the central cleft. The Arg429 side chain is presented as sticks. D, detail of the RNA binding site of the DDX19-RNA complex. E, detail of the nucleotide binding site in the open conformation, with the electron density (2_F_obs – _F_calc) for ADP rendered at 1.5 σ. F, detail of the nucleotide binding site in the RNA complex, with the electron density (2_F_obs –_F_calc) for Mg-ADPNP rendered at 1.5 σ. In all panels, the conserved domain-1 (yellow), the conserved domain-2 (red), and the N-terminal flanking sequence (green) are indicated.

FIGURE 2.

FIGURE 2.

Role of the N-terminal flanking sequence in the regulation of DDX19 ATPase activity. A, schematic diagram of the DDX19 protein constructs used in this study (not drawn to scale). N-term represents the N terminus. B, relative ATPase activities of DDX19 protein constructs in the presence of between 0 and 0.5 mg/ml ssRNA.

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References

    1. Lorsch, J. R., and Herschlag, D. (1998) Biochemistry 37 2194–2206 - PubMed
    1. Jankowsky, E., Gross, C. H., Shuman, S., and Pyle, A. M. (2001) Science 291 121–125 - PubMed
    1. Tran, E. J., Zhou, Y., Corbett, A. H., and Wente, S. R. (2007) Mol. Cell 28 850–859 - PubMed
    1. Cordin, O., Banroques, J., Tanner, N. K., and Linder, P. (2006) Gene (Amst.) 367 17–37 - PubMed
    1. Jankowsky, E., and Fairman, M. E. (2007) Curr. Opin. Struct. Biol. 17 316–324 - PubMed

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