2bq1
From Proteopedia
Ribonucleotide reductase class 1b holocomplex R1E,R2F from Salmonella typhimurium
Structural highlights
FunctionRIR3_SALTY Provides the precursors necessary for DNA synthesis. Catalyzes the biosynthesis of deoxyribonucleotides from the corresponding ribonucleotides. R1E contains the binding sites for both substrates and allosteric effectors and carries out the actual reduction of the ribonucleotide. 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 PubMedRibonucleotide reductase is an indispensable enzyme for all cells, since it catalyses the biosynthesis of the precursors necessary for both building and repairing DNA. The ribonucleotide reductase class I enzymes, present in all mammals as well as in many prokaryotes and DNA viruses, are composed mostly of two homodimeric proteins, R1 and R2. The reaction involves long-range radical transfer between the two proteins. Here, we present the first crystal structure of a ribonucleotide reductase R1/R2 holocomplex. The biological relevance of this complex is based on the binding of the R2 C terminus in the hydrophobic cleft of R1, an interaction proven to be crucial for enzyme activity, and by the fact that all conserved amino acid residues in R2 are facing the R1 active sites. We suggest that the asymmetric R1/R2 complex observed in the 4A crystal structure of Salmonella typhimurium ribonucleotide reductase represents an intermediate stage in the reaction cycle, and at the moment of reaction the homodimers transiently form a tight symmetric complex. The first holocomplex structure of ribonucleotide reductase gives new insight into its mechanism of action.,Uppsten M, Farnegardh M, Domkin V, Uhlin U J Mol Biol. 2006 Jun 2;359(2):365-77. Epub 2006 Mar 31. PMID:16631785[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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