1BIQ image
Deposition Date 1998-06-18
Release Date 1999-01-13
Last Version Date 2023-08-02
Entry Detail
PDB ID:
1BIQ
Keywords:
Title:
RIBONUCLEOSIDE-DIPHOSPHATE REDUCTASE 1 BETA CHAIN MUTANT E238A
Biological Source:
Source Organism:
Escherichia coli (Taxon ID: 562)
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.05 Å
R-Value Free:
0.26
R-Value Work:
0.19
R-Value Observed:
0.19
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:PROTEIN R2 OF RIBONUCLEOTIDE REDUCTASE
Gene (Uniprot):nrdB
Mutations:Y122F, E238A
Chain IDs:A
Chain Length:375
Number of Molecules:1
Biological Source:Escherichia coli
Polymer Type:polypeptide(L)
Molecule:PROTEIN R2 OF RIBONUCLEOTIDE REDUCTASE
Gene (Uniprot):nrdB
Mutations:Y122F, E238A
Chain IDs:B
Chain Length:375
Number of Molecules:1
Biological Source:Escherichia coli
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
MTY A TYR META-TYROSINE
Primary Citation
Crystal structures of two self-hydroxylating ribonucleotide reductase protein R2 mutants: structural basis for the oxygen-insertion step of hydroxylation reactions catalyzed by diiron proteins.
Biochemistry 37 10798 10807 (1998)
PMID: 9692970 DOI: 10.1021/bi9806403

Abstact

The R2 protein of ribonucleotide reductase catalyzes the dioxygen-dependent one-electron oxidation of Tyr122 at a diiron-carboxylate site. Methane monooxygenase and related hydroxylases catalyze hydrocarbon hydroxylation at diiron sites structurally related to the one in R2. In protein R2, the likely reaction site for dioxygen is close to Phe208. The crystal structure of an iron ligand mutant R2, Y122F/E238A, reveals the hydroxylation of Phe208 at the meta, or epsilon-, ring position and the subsequent coordination of this residue to the diiron site. In another mutant, F208Y, the "foreign" residue Tyr208 is hydroxylated to Dopa. The structures of apo and diferrous F208Y presented here suggest that Tyr208 is coordinated to the iron site of F208Y throughout the Dopa generation cycle. Together, the structural data on these two mutants suggest two possible reaction geometries for the hydroxylation reaction catalyzed by these modified R2 diiron sites, geometries which might be relevant for the hydroxylation reaction catalyzed by other diiron sites such as methane monooxygenase. A critical role for residue Glu238 in directing the oxidative power of the reactive intermediate toward oxidation of Tyr122 is proposed.

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Primary Citation of related structures