1qfn
From Proteopedia
GLUTAREDOXIN-1-RIBONUCLEOTIDE REDUCTASE B1 MIXED DISULFIDE BOND
Structural highlights
Function[GLRX1_ECOLI] The disulfide bond functions as an electron carrier in the glutathione-dependent synthesis of deoxyribonucleotides by the enzyme ribonucleotide reductase. In addition, it is also involved in reducing some disulfide bonds in a coupled system with glutathione reductase. [RIR1_ECOLI] Provides the precursors necessary for DNA synthesis. Catalyzes the biosynthesis of deoxyribonucleotides from the corresponding ribonucleotides. R1 contains the binding sites for both substrates and allosteric effectors and carries out the actual reduction of the ribonucleotide. It also provides redox-active cysteines. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe reduction equivalents necessary for the ribonucleotide reductase (RNR)-catalyzed production of deoxyribonucleotides are provided by glutaredoxin (Grx) or thioredoxin (Trx). The initial location for transfer of reducing equivalents to RNR is located at the C terminus of the B1 subunit and involves the reduction of a disulfide between Cys754 and Cys759. We have used a 25-mer peptide corresponding to residues 737-761 of RNR B1 (C754-->S) to synthesize a stable mixed disulfide with Escherichia coli Grx-1 (C14-->S) resembling the structure of an intermediate in the reaction. The high-resolution solution structure of the mixed disulfide has been obtained by NMR with an RMSD of 0.56 A for all the backbone atoms of the protein and the well-defined portion of the peptide. The binding interactions responsible for specificity have been identified demonstrating the importance of electrostatic interactions in this system and providing a rationale for the specificity of the Grx-RNR interaction. The disulfide is buried in this complex, implying a solely intra-molecular mechanism of reduction in contrast to the previously determined structure of the glutathione complex where the disulfide was exposed; mutagenesis studies have shown the relevance of intermolecular reduction processes. Substantial conformational changes in the helices of the protein are associated with peptide binding which have significant mechanistic implications for protein disulfide reduction by glutaredoxins. Binding specificity and mechanistic insight into glutaredoxin-catalyzed protein disulfide reduction.,Berardi MJ, Bushweller JH J Mol Biol. 1999 Sep 10;292(1):151-61. PMID:10493864[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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