title: EPR distance measurements support a model for long-range radical initiation in E. coli ribonucleotide reductase.
abstract: The class I E. coli ribonucleotide reductase, composed of homodimers of R1 and R2, catalyzes the conversion of nucleoside diphosphates to deoxynucleoside diphosphates. The reduction process involves the tyrosyl radical on R2 that generates a transient thiyl radical on R1 over a proposed distance of 35 A. A mechanism-based inhibitor, 2'-azido-2'-deoxyuridine-5'-diphosphate, that reduces the tyrosyl radical on R2 and forms a nitrogen-centered radical on R1 has provided a method to measure the diagonal distance between the two subunits. PELDOR and DQC paramagnetic resonance methods give rise to a distance of 48 A, similar to that calculated from a docking model of the R1 and R2 structures.
authors.affiliation: Institute of Physical and Theoretical Chemistry and BMRZ, University of Frankfurt, D-60439 Frankfurt, Germany. bennati@chemie.uni-frankfurt.de
authors.forename: Marina
authors.initials: M
authors.lastname: Bennati
authors.forename: John H
authors.initials: JH
authors.lastname: Robblee
authors.forename: Veronica
authors.initials: V
authors.lastname: Mugnaini
authors.forename: Joanne
authors.initials: J
authors.lastname: Stubbe
authors.forename: Jack H
authors.initials: JH
authors.lastname: Freed
authors.forename: Peter
authors.initials: P
authors.lastname: Borbat
mesh_terms: D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D004926:Escherichia coli / Q000201:enzymology*; D005609:Free Radicals / Q000737:chemistry*; D008954:Models, Biological; D012264:Ribonucleotide Reductases / Q000378:metabolism*; D013997:Time Factors
chemical_list: D005609:Free Radicals; D012264:Ribonucleotide Reductases