Structure of a trapped radical transfer pathway within a ribonucleotide reductase holocomplex

• Autor: Kang, Gyunghoon ; Taguchi, Alexander T ; Stubbe, JoAnne ; Drennan, Catherine L
• Assuntos: Biocatalysis ; Biosynthesis ; Catalytic Domain ; Cryoelectron Microscopy ; Deoxyribonucleic acid ; DNA ; Electron microscopy ; Escherichia coli Proteins - chemistry ; Escherichia coli Proteins - genetics ; Holoenzymes - chemistry ; Holoenzymes - genetics ; Microscopy ; Protein Conformation ; Reductase ; Reductases ; Ribonucleotide reductase ; Ribonucleotide Reductases - chemistry ; Ribonucleotide Reductases - genetics ; Tyrosine - chemistry ; Visualization
• É parte de: Science (American Association for the Advancement of Science), 2020-04, Vol.368 (6489), p.424-427
• Notas: ObjectType-Article-1
  SourceType-Scholarly Journals-1
  ObjectType-Feature-2
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  Current address for ATT: RubrYc Therapeutics, San Carlos CA, United States
  Author contributions: G.K. and A.T.T. performed sample optimization for cryo-EM sample preparation. G.K. collected and processed the cryo-EM data, and built and refined the structure. G.K., J.S., and C.L.D. wrote the manuscript. J.S. and C.L.D. supervised the research and led project conceptualization.
  
• Descrição: 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.
  
• Editor: United States: The American Association for the Advancement of Science
  
• Idioma: Inglês