Structural Elucidation of the Reduced Mn(III)/Fe(III) Intermediate of the Radical-Initiating Metallocofactor in <i>Chlamydia trachomatis</i> Ribonucleotide Reductase.

ABSTRACT: Ribonucleotide reductases (RNRs) are the sole de novo source of deoxyribonucleotides for DNA synthesis and repair across all organisms and carry out their reaction via a radical mechanism. RNR from Chlamydia trachomatis generates its turnover-initiating cysteinyl radical by long-range reduction of a Mn(IV)/Fe(III) cofactor, producing a Mn(III)/Fe(III) intermediate. Herein, we characterize the protonation states of the inorganic ligands in this reduced state using advanced pulse electron paramagnetic resonance (EPR) spectroscopy and ²H-isotope labeling. A strongly coupled deuteron is observed by hyperfine sublevel correlation (HYSCORE) spectroscopy experiments and indicates the presence of a bridging hydroxo ligand. Isotope-dependent EPR line broadening analysis and

SUBMITTER: Martinie RJ 

PROVIDER: S-EPMC11883743 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature