Book of Abstracts: Albany 2005

category image Volume 22
No. 6
June 2005

Structural Principles of Small RNA Duplex Recognition

The p19 protein from the tombusvirus is a viral suppressor of RNA silencing and has been shown to bind specifically to small interfering RNAs (siRNAs). We have recently determined the 1.85 Å crystal structure of p19 bound to a 21-nucleotide siRNA with a 19 base pair duplex region (1). In the complex, p19 forms a dimer, which has a continuous eight-stranded β-sheet in the center and two α-helical ?arms? protruding from opposite ends. While the RNA duplex is cradled within the saddle-like β-sheet surface, two ?arms? act as a caliper to measure the length of the duplex region, with a tryptophan-pair ?hand? projecting to stack over the terminal RNA base pair on either side. Our structural findings and comparison with another p19-siRNA complex (2) establish principles of the specific RNA selection based on the length of the duplex region and give rise to speculations of how p19 accommodates siRNAs of a range of lengths.

References and Footnotes
  1. Ye, K., Malinina, L., and Patel, D. J. Nature 426, 874-878 (2003).
  2. Vargason, J. M., Szittya, G., Burgyan, J., and Tanaka Hall, T. M. Cell 115, 799-811 (2003).

Lucy Malinina*
Keqiong Ye
Dinshaw J. Patel

Structural Biology Program
Memorial Sloan-Kettering Cancer Center
New York, New York 10021, USA

*Phone: 1-212-639-8561
Fax: 1-212-717-3066
Email: lucy@mskcc.org