Crystal Structure of the C-Terminal RNase III Domain of Human Dicer

Experimental Data Snapshot

  • Resolution: 2.00 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.212 

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Homodimeric Structure and Double-stranded RNA Cleavage Activity of the C-terminal RNase III Domain of Human Dicer

Takeshita, D.Zenno, S.Lee, W.C.Nagata, K.Saigo, K.Tanokura, M.

(2007) J Mol Biol 374: 106-120

  • DOI: https://doi.org/10.1016/j.jmb.2007.08.069
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Human Dicer contains two RNase III domains (RNase IIIa and RNase IIIb) that are responsible for the production of short interfering RNAs and microRNAs. These small RNAs induce gene silencing known as RNA interference. Here, we report the crystal structure of the C-terminal RNase III domain (RNase IIIb) of human Dicer at 2.0 A resolution. The structure revealed that the RNase IIIb domain can form a tightly associated homodimer, which is similar to the dimers of the bacterial RNase III domains and the two RNase III domains of Giardia Dicer. Biochemical analysis showed that the RNase IIIb homodimer can cleave double-stranded RNAs (dsRNAs), and generate short dsRNAs with 2 nt 3' overhang, which is characteristic of RNase III products. The RNase IIIb domain contained two magnesium ions per monomer around the active site. The distance between two Mg-1 ions is approximately 20.6 A, almost identical with those observed in bacterial RNase III enzymes and Giardia Dicer, while the locations of two Mg-2 ions were not conserved at all. We presume that Mg-1 ions act as catalysts for dsRNA cleavage, while Mg-2 ions are involved in RNA binding.

  • Organizational Affiliation

    Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Endoribonuclease Dicer
A, B, C
200Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for Q9UPY3 (Homo sapiens)
Explore Q9UPY3 
Go to UniProtKB:  Q9UPY3
GTEx:  ENSG00000100697 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9UPY3
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.00 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.212 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 88.602α = 90
b = 199.743β = 90
c = 119.64γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-11-06
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.2: 2023-10-25
    Changes: Data collection, Database references, Derived calculations, Refinement description