Meipei She1, Carolyn J. Decker2, Dmitri I. Svergun3,4, Adam Round3, Nan Chen1, Denise Muhlrad2, Roy Parker2 and Haiwei Song1,5,#
1 Department of Biological Sciences, National University of Singapore, Singapore
2 Institute of Molecular and Cell Biology, Proteos, Singapore
3 Equal first authors
1 Laboratory of Macromolecular Structure, Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), 61 Biopolis Drive, Proteos, Singapore 138673.
2 Department of Molecular and Cellular Biology and Howard Hughes Medical Institute, University of Arizona, Tucson, AZ 85721, USA.
3 Hamburg Outstation, European Molecular Biology Laboratory, Hamburg, Germany
4 Institute of Crystallography, Russian Academy of Sciences, Leninsky pr. 59, 117333 Moscow, Russia
5 Department of Biological Sciences, National University of Singapore, 14 Science Drive, Singapore 117543.
#Correspondence should be addressed to H.S.(email@example.com).
A critical step in mRNA degradation is the removal of the 5' cap structure, which is catalyzed by the Dcp1-Dcp2 complex. The crystal structure of a S. pombe Dcp1p-Dcp2n complex combined with small-angle X-ray scattering analysis (SAXS) reveals that Dcp2p exists in open and closed conformations, with the closed complex being, or closely resembling the catalytically more active form. This suggests that a conformational change between these open and closed complexes might control decapping. A bipartite RNA binding channel containing the catalytic site and Box B motif is identified with a bound ATP located in the catalytic pocket in the closed complex, suggesting possible interactions that facilitate substrate binding. Dcp1 stimulates the activity of Dcp2 by promoting and/or stabilizing the closed complex. Notably, the interface of Dcp1 and Dcp2 is not fully conserved, explaining why the Dcp1-Dcp2 interaction in higher eukaryotes requires an additional factor.
Published online in Mol. Cell 14 February 2008;
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