Download MendeleyStructural basis for targeting of human RNA helicase DDX3 by poxvirus protein K7
Oda, S., Schroder, M., Khan, A.R.(2009) Structure 17: 1528-1537
- PubMed: 19913487
- DOI: https://doi.org/10.1016/j.str.2009.09.005
- Primary Citation of Related Structures:
3JRV - PubMed Abstract:
Poxviruses are DNA viruses that express numerous proteins to subvert the host immune response. Vaccinia virus protein K7 adopts a Bcl-2 fold and displays structural and functional similarities to Toll-like receptor antagonist A52. Both proteins interact with IRAK2 and TRAF6 and suppress TLR-dependent NF-kappaB activation. However, unlike A52, K7 also forms a complex with RNA helicase DDX3 and antagonizes interferon-beta promoter induction. We have narrowed the K7 binding site to an N-terminal peptide motif of DDX3 ahead of its core RNA-helicase domains. The crystal structure of full-length K7 in complex with the DDX3 peptide reveals a thumblike projection of tandem phenalyalanine residues of DDX3 into a deep hydrophobic cleft. Mutagenesis of these phenylalanines abolishes the effects of DDX3 on interferon-beta promoter induction. The structure of K7-DDX3 reveals a novel binding mode by a viral Bcl-2 protein that antagonizes a key pathway in innate immunity.
Organizational Affiliation:
School of Biochemistry and Immunology, Trinity College, Dublin, Dublin 2, Ireland.
