Class Ib Ribonucleotide Reductases: Activation of a Peroxido-MnIIMnIII to Generate a Reactive Oxo-MnIIIMnIV Oxidant
Year: 2024
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide In the postulated catalytic cycle of class Ib Mn 2 ribonucleotide reductases (RNRs), a Mn II 2 core is suggested to react with superoxide (O 2 ·– ) to generate peroxido-Mn II Mn III and oxo-Mn III Mn IV entities prior to proton-coupled electron transfer (PCET) oxidation of tyrosine. There is limited experimental support for this mechanism. We demonstrate that [Mn II 2 (BPMP)(OAc) 2 ](ClO 4 ) ( 1, HBPMP = 2,6-bis[(bis(2 pyridylmethyl)amino)methyl]-4-methylphenol) was converted to peroxido-Mn II Mn III ( 2 ) in the presence of superoxide anion that converted to (μ-O)(μ-OH)Mn III Mn IV ( 3 ) via the addition of an H + -donor ( p- TsOH) or (μ-O) 2 Mn III Mn IV ( 4 ) upon warming to room temperature. The physical properties of 3 and 4 were probed using UV–vis, EPR, X-ray absorption, and IR spectroscopies and mass spectrometry. Compounds 3 and 4 were capable of phenol oxidation to yield a phenoxyl radical via a concerted PCET oxidation, supporting the proposed mechanism of tyrosyl radical cofactor generation in RNRs. The synthetic models demonstrate that the postulated O 2 /Mn 2 /tyrosine activation mechanism in class Ib Mn 2 RNRs is plausible and provides spectral insights into intermediates currently elusive in the native enzyme.
Source: Inorganic Chemistry
Authors: Lorna Doyle, Adriana Magherusan, Shuangning Xu, Kayleigh Murphy, Erik R. Farquhar, Florian Molton, Carole Duboc, Lawrence Que, Aidan R. McDonald
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Funders: U.S. Department of Energy, LABoratoires d’EXcellence ARCANE, European Commission, Science Foundation Ireland, Agence Nationale de la Recherche, Irish Research Council, National Institutes of Health, Office of Science, National Institute of General Medical Sciences, Basic Energy Sciences, H2020 European Research Council, CHIST-ERA
Awards: G1183670895, G1229526393, Selective molecular O2 reduction catalysts Toward noble metal-free H2/O2 fuel cells, G1286251239, G137528073, CBH-EUR-GS, G1817966306, G2049125742, G2121614283, G2310872092, G2371548206, G2389725886, G2659019386, G292453335, G303061748, Grenoble, une chimie bio-motivée, G3914891588, G4775162344, G495301720, G498139845, G5570207115, G5677597355, G5903178873, G6550344761, G6803667113, Bioinorganic Nucleophilic Reactivity of Metal-Bound Superoxide, G7283024673, G7808826240, G8382000481, Late First-Row Transition Metal-Oxo Complexes for C–H Bond Activation, G8668274974, O-O Bond Activation (and Formation) at Bimetallic Enzyme Active Sites, G8925327636, G8945569637, G8964069747, G8967554772, G911061179, G969889393, G994248709
OpenAlex ID: W4390940247