Download MendeleyInsights Into RNA Unwinding and ATP Hydrolysis by the Flavivirus Ns3 Protein.
Luo, D., Xu, T., Watson, R.P., Scherer-Becker, D., Sampath, A., Jahnke, W., Yeong, S.S., Wang, C.H., Lim, S.P., Strongin, A., Vasudevan, S.G., Lescar, J.(2008) EMBO J 27: 3209
- PubMed: 19008861
- DOI: https://doi.org/10.1038/emboj.2008.232
- Primary Citation of Related Structures:
2JLQ, 2JLR, 2JLS, 2JLU, 2JLV, 2JLW, 2JLX, 2JLY, 2JLZ - PubMed Abstract:
Together with the NS5 polymerase, the NS3 helicase has a pivotal function in flavivirus RNA replication and constitutes an important drug target. We captured the dengue virus NS3 helicase at several stages along the catalytic pathway including bound to single-stranded (ss) RNA, to an ATP analogue, to a transition-state analogue and to ATP hydrolysis products. RNA recognition appears largely sequence independent in a way remarkably similar to eukaryotic DEAD box proteins Vasa and eIF4AIII. On ssRNA binding, the NS3 enzyme switches to a catalytic-competent state imparted by an inward movement of the P-loop, interdomain closure and a change in the divalent metal coordination shell, providing a structural basis for RNA-stimulated ATP hydrolysis. These structures demonstrate for the first time large quaternary changes in the flaviviridae helicase, identify the catalytic water molecule and point to a beta-hairpin that protrudes from subdomain 2, as a critical element for dsRNA unwinding. They also suggest how NS3 could exert an effect as an RNA-anchoring device and thus participate both in flavivirus RNA replication and assembly.
Organizational Affiliation:
Structural & Computational Biology Division, School of Biological Sciences, Nanyang Technological University, Singapore.
