Crystal structure of Bst-RNase HIII in complex with Mg2+

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.220 
  • R-Value Observed: 0.220 

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Crystal structure and structure-based mutational analyses of RNase HIII from Bacillus stearothermophilus: a new type 2 RNase H with TBP-like substrate-binding domain at the N terminus

Chon, H.Matsumura, H.Koga, Y.Takano, K.Kanaya, S.

(2006) J Mol Biol 356: 165-178

  • DOI: https://doi.org/10.1016/j.jmb.2005.11.017
  • Primary Citation of Related Structures:  
    2D0A, 2D0B, 2D0C

  • PubMed Abstract: 

    Ribonuclease HIII (Bst-RNase HIII) from the moderate thermophile Bacillus stearothermophilus is a type 2 RNase H but shows poor amino acid sequence identity with another type 2 RNase H, RNase HII. It is composed of 310 amino acid residues and acts as a monomer. Bst-RNase HIII has a large N-terminal extension with unknown function and a unique active-site motif (DEDE), both of which are characteristics common to RNases HIII. To understand the role of these N-terminal extension and active-site residues, the crystal structure of Bst-RNase HIII was determined in both metal-free and metal-bound forms at 2.1-2.6 angstroms resolutions. According to these structures, Bst-RNase HIII consists of the N-terminal domain and C-terminal RNase H domain. The structures of the N and C-terminal domains were similar to those of TATA-box binding proteins and archaeal RNases HII, respectively. The steric configurations of the four conserved active-site residues were very similar to those of other type 1 and type 2 RNases H. Single Mn and Mg ions were coordinated with Asp97, Glu98, and Asp202, which correspond to Asp10, Glu48, and Asp70 of Escherichia coli RNase HI, respectively. The mutational studies indicated that the replacement of either one of these residues with Ala resulted in a great reduction of the enzymatic activity. Overproduction, purification, and characterization of the Bst-RNase HIII derivatives with N and/or C-terminal truncations indicated that the N-terminal domain and C-terminal helix are involved in substrate binding, but the former contributes to substrate binding more greatly than the latter.

  • Organizational Affiliation

    Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ribonuclease HIII310Geobacillus stearothermophilusMutation(s): 0 
Find proteins for Q6L6Q4 (Geobacillus stearothermophilus)
Explore Q6L6Q4 
Go to UniProtKB:  Q6L6Q4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ6L6Q4
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on MG

Download Ideal Coordinates CCD File 
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.220 
  • R-Value Observed: 0.220 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.163α = 90
b = 109.465β = 90
c = 48.412γ = 90
Software Package:
Software NamePurpose

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-07-18
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance