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

Abstract

Caught in the act Proton-coupled electron transfer (PCET) is an important process for moving electrons through proteins and requires precise positioning of suitable proton and electron carriers. Kang et al. determined a cryo–electron microscopy structure of the active complex formed by ribonucleotide reductase that allows for PCET between two protein subunits over a total distance of ∼35 angstroms. Several interventions that stabilized the radical en route also stabilized the complex and allowed for visualization of the interface between the two subunits and the full network of residues that permit PCET. Science , this issue p. 424