Biological Assembly 1  

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 89.08 kDa 
• Atom Count: 5,931 
• Modelled Residue Count: 681 
• Deposited Residue Count: 750 
• Unique protein chains: 1

 1XIK

RIBONUCLEOSIDE-DIPHOSPHATE REDUCTASE 1 BETA CHAIN

• PDB DOI: 10.2210/pdb1XIK/pdb

• Classification: OXIDOREDUCTASE
• Organism(s): Escherichia coli
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 1996-08-06 Released: 1997-03-12 
• Deposition Author(s): Logan, D.T., Su, X.-D., Aberg, A., Regnstrom, K., Hajdu, J., Eklund, H., Nordlund, P.

---

Experimental Data Snapshot

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

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

• PubMed: 8805591 
• DOI: 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.

---

Related Citations: 

• Structure and Function of the Escherichia Coli Ribonucleotide Reductase Protein R2
  Nordlund, P., Eklund, H.
  (1993) J Mol Biol 232: 123

---

Organizational Affiliation: 

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

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
PROTEIN R2 OF RIBONUCLEOTIDE REDUCTASE	A, B	375	Escherichia coli	Mutation(s): 0  EC: 1.17.4.1
UniProt
Find proteins for P69924 (Escherichia coli (strain K12)) Explore P69924  Go to UniProtKB:  P69924

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
HG	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	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 = 73.44	α = 90
b = 83.53	β = 90
c = 113.7	γ = 90

Software Package:

Software Name	Purpose
AMoRE	phasing
TNT	refinement
MOSFLM	data reduction
CCP4	data scaling

Structure Validation

Entry History 

Deposition Data

• Released Date: 1997-03-12 
Deposition Author(s): Logan, D.T., Su, X.-D., Aberg, A., Regnstrom, K., Hajdu, J., Eklund, H., Nordlund, P.

Revision History  

• 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