PMID:11875520

Citation	Sintchak, MD, Arjara, G, Kellogg, BA, Stubbe, J and Drennan, CL (2002) The crystal structure of class II ribonucleotide reductase reveals how an allosterically regulated monomer mimics a dimer. Nat. Struct. Biol. 9:293-300
Abstract	Ribonucleotide reductases (RNRs) catalyze the conversion of ribonucleotides to deoxyribonucleotides, an essential step in DNA biosynthesis and repair. Here we present the crystal structure of class II (coenzyme B12-dependent) ribonucleoside triphosphate reductase (RTPR) from Lactobacillus leichmannii in the apo enzyme form and in complex with the B12 analog adeninylpentylcobalamin at 1.75 and 2.0 A resolution, respectively. This monomeric, allosterically regulated class II RNR retains all the key structural features associated with the catalytic and regulatory machinery of oligomeric RNRs. Surprisingly, the dimer interface responsible for effector binding in class I RNR is preserved through a single 130-residue insertion in the class II structure. Thus, L. leichmannii RNR is a paradigm for the simplest structural entity capable of ribonucleotide reduction, a reaction linking the RNA and DNA worlds.
Links	PubMed Online version:10.1038/nsb774
Keywords	Allosteric Regulation; Apoenzymes/chemistry; Apoenzymes/metabolism; Binding Sites; Catalysis; Conserved Sequence; Crystallography, X-Ray; Dimerization; Evolution, Molecular; Free Radicals/metabolism; Lactobacillus/enzymology; Models, Molecular; Organometallic Compounds/metabolism; Protein Structure, Quaternary; Protein Structure, Secondary; Ribonucleotide Reductases/chemistry; Ribonucleotide Reductases/classification; Ribonucleotide Reductases/metabolism; Structure-Activity Relationship; Substrate Specificity; Sulfur/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
9CAUD:A0A0K2CZX3		GO:0009186: deoxyribonucleoside diphosphate metabolic process	ECO:0000314:		P		RNRs catalyze conversion of ribonucleotides to deoxyribonucleotides	complete CACAO 11632

References

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