1UQ5

RICIN A-CHAIN (RECOMBINANT) N122A MUTANT


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.40 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.179 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

The Effect of Mutations Surrounding and within the Active Site on the Catalytic Activity of Ricin a Chain

Marsden, C.J.Fulop, V.Day, P.Lord, J.M.

(2004) Eur J Biochem 271: 153

  • DOI: https://doi.org/10.1046/j.1432-1033.2003.03914.x
  • Primary Citation of Related Structures:  
    1UQ4, 1UQ5

  • PubMed Abstract: 

    Models for the binding of the sarcin-ricin loop (SRL) of 28S ribosomal RNA to ricin A chain (RTA) suggest that several surface exposed arginine residues surrounding the active site cleft make important interactions with the RNA substrate. The data presented in this study suggest differing roles for these arginyl residues. Substitution of Arg48 or Arg213 with Ala lowered the activity of RTA 10-fold. Furthermore, substitution of Arg213 with Asp lowered the activity of RTA 100-fold. The crystal structure of this RTA variant showed it to have an unaltered tertiary structure, suggesting that the positively charged state of Arg213 is crucial for activity. Substitution of Arg258 with Ala had no effect on activity, although substitution with Asp lowered activity 10-fold. Substitution of Arg134 prevented expression of folded protein, suggesting a structural role for this residue. Several models have been proposed for the binding of the SRL to the active site of RTA in which the principal difference lies in the conformation of the second 'G' in the target GAGA motif in the 28S rRNA substrate. In one model, the sidechain of Asn122 is proposed to make interactions with this G, whereas another model proposes interactions with Asp75 and Asn78. Site-directed mutagenesis of these residues of RTA favours the first of these models, as substitution of Asn78 with Ser yielded an RTA variant whose activity was essentially wild-type, whereas substitution of Asn122 reduced activity 37.5-fold. Substitution of Asp75 failed to yield significant folded protein, suggesting a structural role for this residue.


  • Organizational Affiliation

    Department of Biological Sciences, University of Warwick, Coventry, UK.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
RICIN263Ricinus communisMutation(s): 1 
EC: 3.2.2.22
UniProt
Find proteins for P02879 (Ricinus communis)
Explore P02879 
Go to UniProtKB:  P02879
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02879
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.40 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.179 
  • Space Group: P 41 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.5α = 90
b = 67.5β = 90
c = 140.6γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling
CCP4phasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-01-02
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-01-17
    Changes: Data collection
  • Version 1.4: 2023-12-13
    Changes: Data collection, Database references, Other, Refinement description