6w4x
From Proteopedia
Holocomplex of E. coli class Ia ribonucleotide reductase with GDP and TTP
Structural highlights
FunctionRIR1_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. Publication Abstract from PubMedRibonucleotide reductases (RNRs) are a diverse family of enzymes that are alone capable of generating 2'-deoxynucleotides de novo and are thus critical in DNA biosynthesis and repair. The nucleotide reduction reaction in all RNRs requires the generation of a transient active site thiyl radical, and in class I RNRs this process involves a long-range radical transfer between two subunits, alpha and beta. Due to the transient subunit association, an atomic resolution structure of an active alpha2beta2 RNR complex has been elusive. Here we use a doubly-substituted beta2, E52Q/(2,3,5)-trifluorotyrosine122-beta2 to trap wildtype-alpha2 in long-lived alpha2beta2 complex. We report the structure of this complex by cryo-electron microscopy to 3.6-A resolution, allowing for structural visualization of a 32-A-long radical transfer pathway that affords RNR activity. Structure of a trapped radical transfer pathway within a ribonucleotide reductase holocomplex.,Kang G, Taguchi AT, Stubbe J, Drennan CL Science. 2020 Mar 26. pii: science.aba6794. doi: 10.1126/science.aba6794. PMID:32217749[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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