Structure of a trapped radical transfer pathway within a ribonucleotide reductase holocomplex.Kang, G., Taguchi, A.T., Stubbe, J., Drennan, C.L.
(2020) Science 368: 424-427
- PubMed: 32217749
- DOI: https://doi.org/10.1126/science.aba6794
- Primary Citation of Related Structures:
- PubMed Abstract:
Ribonucleotide 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, α and β. Because of the transient subunit association, an atomic resolution structure of an active α2β2 RNR complex has been elusive. We used a doubly substituted β2, E52Q/(2,3,5)-trifluorotyrosine122-β2, to trap wild-type α2 in a long-lived α2β2 complex. We report the structure of this complex by means of cryo-electron microscopy to 3.6-angstrom resolution, allowing for structural visualization of a 32-angstrom-long radical transfer pathway that affords RNR activity.
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