1XIK

RIBONUCLEOSIDE-DIPHOSPHATE REDUCTASE 1 BETA CHAIN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.280 
  • R-Value Work: 0.206 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Crystal structure of reduced protein R2 of ribonucleotide reductase: the structural basis for oxygen activation at a dinuclear iron site.

Logan, D.T.Su, X.D.Aberg, A.Regnstrom, K.Hajdu, J.Eklund, H.Nordlund, P.

(1996) Structure 4: 1053-1064

  • DOI: https://doi.org/10.1016/s0969-2126(96)00112-8
  • Primary Citation of Related Structures:  
    1PFR, 1XIK

  • PubMed Abstract: 

    Ribonucleotide reductases (RNRs) catalyze the formation of the deoxyribonucleotides that are essential for DNA synthesis. The R2 subunit of Escherichia coli RNR is a homodimer containing one dinuclear iron centre per monomer. A tyrosyl radical is essential for catalysis, and is formed via a reaction in which the reduced, diferrous form of the iron centre activates dioxygen. To help understand the mechanism of oxygen activation, we examined the structure of the diferrous form of R2. The crystal structures of reduced forms of both wild type R2 and a mutant of R2 (Ser211--> Ala) have been determined at 1.7 A and 2.2 A resolution, respectively. The diferrous iron centre was compared to the previously determined structure of the oxidized, diferric form of R2. In both forms of R2 the iron centre is coordinated by the same carboxylate dominated ligand sphere, but in the reduced form there are clear conformational changes in three of the carboxylate ligands and the bridging mu-oxo group and two water molecules are lost. In the reduced form of R2 the coordination number decreases from six to four for both ferrous ions, explaining their high reactivity towards dioxygen. The structure of the mutant Ser211--> Ala, known to have impaired reduction kinetics, shows a large conformational change in one of the neighbouring helices although the iron coordination is very similar to the wild type protein. Carboxylate shifts are often important for carboxylate coordinated metal clusters; they allow the metals to achieve different coordination modes in redox reactions. In the case of reduced R2 these carboxylate shifts allow the formation of accessible reaction sites for dioxygen. The Ser211--> Ala mutant displays a conformational change in the helix containing the mutation, explaining its altered reduction kinetics.


  • Organizational Affiliation

    Department of Molecular Biology University of Stockholm S-106 91 Stockholm Sweden.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
PROTEIN R2 OF RIBONUCLEOTIDE REDUCTASE
A, B
375Escherichia coliMutation(s): 0 
EC: 1.17.4.1
UniProt
Find proteins for P69924 (Escherichia coli (strain K12))
Explore P69924 
Go to UniProtKB:  P69924
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP69924
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
HG
Query on HG

Download Ideal Coordinates CCD File 
E [auth A]
F [auth A]
G [auth A]
H [auth A]
I [auth A]
E [auth A],
F [auth A],
G [auth A],
H [auth A],
I [auth A],
J [auth A],
M [auth B],
N [auth B],
O [auth B],
P [auth B]
MERCURY (II) ION
Hg
BQPIGGFYSBELGY-UHFFFAOYSA-N
FE2
Query on FE2

Download Ideal Coordinates CCD File 
C [auth A],
D [auth A],
K [auth B],
L [auth B]
FE (II) ION
Fe
CWYNVVGOOAEACU-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.280 
  • R-Value Work: 0.206 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 73.44α = 90
b = 83.53β = 90
c = 113.7γ = 90
Software Package:
Software NamePurpose
AMoREphasing
TNTrefinement
MOSFLMdata reduction
CCP4data scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1997-03-12
    Type: Initial release
  • Version 1.1: 2008-03-03
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-08-09
    Changes: Database references, Derived calculations, Refinement description