Description |
The only crystal structure of full-length Dicer to date is that of G. intestinalis protein (Gi-Dicer), which consists of two endoNDs, PAZ and platform domains. The structure of Gi-Dicer has been likened to a hatchet with the dimeric endoNDs forming the blade and the PAZ at the end of the handle. Gi-Dicer cleaves dsRNA to 25 bps with 2 nt overhang at the 3? end. Using structures of bacterial RNase III-dsRNA and PAZ-nucleic acid complexes as templates, a model of Gi-Dicer - dsRNA complex was proposed. The platform domain between the endoND and PAZ appears to have a positively charged flat surface for dsRNA binding and separates the cleavage site (endoND) from the 3? end (PAZ) by ~25-bps.
Reference:
1. M. Nowotny, W. Yang, Structural and functional modules in RNA interference. Curr Opin Struct Biol 19, 286 (2009).
2. I. J. Macrae, K. Zhou, F. Li, A. Repic, A. N. Brooks, W. Z. Cande, P. D. Adams, J. A. Doudna, Structural basis for double-stranded RNA processing by Dicer. Science 311, 195 (2006).
3. I. J. MacRae, K. Zhou, J. A. Doudna, Structural determinants of RNA recognition and cleavage by Dicer. Nat Struct Mol Biol 14, 934 (2007). |