Radical transfer in E. coli ribonucleotide reductase: a NH₂Y₇₃₁/R₄₁₁A-α mutant unmasks a new conformation of the pathway residue 731.

ABSTRACT: Ribonucleotide reductases (RNRs) catalyze the conversion of ribonucleotides to deoxyribonucleotides in all living organisms. The catalytic cycle of E. coli RNR involves a long-range proton-coupled electron transfer (PCET) from a tyrosyl radical (Y₁₂₂˙) in subunit β2 to a cysteine (C₄₃₉) in the active site of subunit α2, which subsequently initiates nucleotide reduction. This oxidation occurs over 35 Å and involves a specific pathway of redox active amino acids (Y₁₂₂ ↔ [W₄₈?] ↔ Y₃₅₆ in β2 to Y₇₃₁ ↔ Y₇₃₀ ↔ C₄₃₉ in α2). The mechanisms of the PCET steps at the interface of the α2β2 complex remain puzzling due to a lack of structural information for this region. Recently, DFT calculations on the 3-ami

SUBMITTER: Kasanmascheff M 

PROVIDER: S-EPMC5968753 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature