1xjj

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Revision as of 00:10, 25 November 2007

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spinqualitylabelsall models 1xjj, resolution 1.86Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Structural mechanism of allosteric substrate specificity in a ribonucleotide reductase: dGTP complex

Overview

Ribonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides, into deoxyribonucleotides, which constitute the precursor pools used for, DNA synthesis and repair. Imbalances in these pools increase mutational, rates and are detrimental to the cell. Balanced precursor pools are, maintained primarily through the regulation of the RNR substrate, specificity. Here, the molecular mechanism of the allosteric substrate, specificity regulation is revealed through the structures of a dimeric, coenzyme B12-dependent RNR from Thermotoga maritima, both in complexes, with four effector-substrate nucleotide pairs and in three complexes with, only effector. The mechanism is based on the flexibility of loop 2, a key, structural element, which forms a bridge between the specificity effector, and substrate nucleotides. Substrate specificity is achieved as different, effectors and their cognate substrates stabilize specific discrete loop 2, conformations. The mechanism of substrate specificity regulation is, probably general for most class I and class II RNRs.

About this Structure

1XJJ is a Single protein structure of sequence from Thermotoga maritima with MG and DGT as ligands. Active as Ribonucleoside-diphosphate reductase, with EC number 1.17.4.1 Full crystallographic information is available from OCA.

Reference

Structural mechanism of allosteric substrate specificity regulation in a ribonucleotide reductase., Larsson KM, Jordan A, Eliasson R, Reichard P, Logan DT, Nordlund P, Nat Struct Mol Biol. 2004 Nov;11(11):1142-9. Epub 2004 Oct 10. PMID:15475969

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