2ZI0: Crystal Structure Of Tav2bSIRNA COMPLEX

The 2b proteins encoded by cucumovirus act as post-transcriptional gene silencing suppressors to counter host defence during infection. Here we report the crystal structure of Tomato aspermy virus 2b (TAV2b) protein bound to a 19 bp small interfering RNA (siRNA) duplex. TAV2b adopts an all alpha-helix structure and forms a homodimer to measure siRNA duplex in a length-preference mode. TAV2b has a pair of hook-like structures to recognize simultaneously two alpha-helical turns of A-form RNA duplex by fitting its alpha-helix backbone into two adjacent major grooves of siRNA duplex. The conserved pi-stackings between tryptophan and the 5'-terminal base of siRNA duplex from both ends enhance the recognition. TAV2b further oligomerizes to form a dimer of dimers through the conserved leucine-zipper-like motif at its amino-terminal alpha-helix. Biochemical experiments suggest that TAV2b might interfere with the post-transcriptional gene silencing pathway by directly binding to siRNA duplex.
PDB ID: 2ZI0Download
MMDB ID: 65598
PDB Deposition Date: 2008/2/12
Updated in MMDB: 2012/10
Experimental Method:
x-ray diffraction
Resolution: 2.82  Å
Source Organism:
synthetic construct
Similar Structures:
Biological Unit for 2ZI0: tetrameric; determined by author and by software (PISA)
Molecular Components in 2ZI0
Label Count Molecule
Proteins (2 molecules)
Protein 2B(Gene symbol: TAVs2gp2)
Molecule annotation
Nucleotide(1 molecule)
RNA (5'- D(p*ap*gp*ap*cp*ap*gp*cp*ap*up*up*ap*up*gp*cp*up*gp*up*cp*up*up*u)- 3')
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB