Composition and Structure of the Inorganic Core of Relaxed Intermediate X(Y122F) of Escherichia coli Ribonucleotide Reductase.

ABSTRACT: Activation of the diferrous center of the β2 (R2) subunit of the class 1a Escherichia coli ribonucleotide reductases by reaction with O2 followed by one-electron reduction yields a spin-coupled, paramagnetic Fe(III)/Fe(IV) intermediate, denoted X, whose identity has been sought by multiple investigators for over a quarter of a century. To determine the composition and structure of X, the present study has applied (57)Fe, (14,15)N, (17)O, and (1)H electron nuclear double resonance (ENDOR) measurements combined with quantitative measurements of (17)O and (1)H electron paramagnetic resonance line-broadening studies to wild-type X, which is very short-lived, and to X prepared with the Y122F mutant, which has a lifetime of many seconds. Previous studies have established that over several second

SUBMITTER: Doan PE 

PROVIDER: S-EPMC4732524 | biostudies-literature | 2015 Dec

REPOSITORIES: biostudies-literature