2R2F: Ribonucleotide Reductase R2f Protein From Salmonella Typhimurium (Oxidized)

The first class Ib ribonucleotide reductase R2 structure, from Salmonella typhimurium, has been determined at 2.0 A resolution. The overall structure is similar to the Escherichia coli class Ia enzyme despite only 23% sequence identity. The most spectacular difference is the absence of the pleated sheet and adjacent parts present in the E. coli R2 structure; the heart-shaped structure loses its tip. From sequence comparisons, it appears that this feature is shared with all other class Ib enzymes and, in this respect, is more like the mammalian class Ia enzymes. Both the oxidized and reduced iron forms have been investigated. In the ferric iron center, both iron ions are octahedrally coordinated and bridged by one carboxylate and one oxide ion. The ferrous form has lost the bridging oxide ion but is bridged by two carboxylates. Accompanying the change in redox state, helix E changes its conformation from one covering the metal center in the oxidized form to a more open reduced form. A narrow channel is opened which may permit easier access of oxygen to the ferrous iron site and to efficiently generate the tyrosyl radical.
PDB ID: 2R2FDownload
MMDB ID: 12099
PDB Deposition Date: 1998/8/24
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 2.25  Å
Source Organism:
Similar Structures:
Biological Unit for 2R2F: dimeric; determined by author and by software (PISA,PQS)
Molecular Components in 2R2F
Label Count Molecule
Proteins (2 molecules)
Protein (Ribonucleoside-diphosphate Reductase Small Chain)(Gene symbol: nrdF)
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB