The R2 subunit of Escherichia coli ribonucleotide reductase (RNR) contains a stable tyrosyl radical (•Y122) diferric cluster cofactor. Earlier studies on the cofactor assembly reaction detected paramagnetic intermediate, X, that was found to be kinetically competent oxidize Y122. Studies using rapid freeze-quench (RFQ) Mössbauer and EPR spectroscopies led proposal X is comprised two high spin ferric ions S = 1/2 ligand radical, mutually coupled give ground state (Ravi, N.; Bollinger, J. M.,...

The class Ib ribonucleotide reductase of Escherichia coli can initiate reduction nucleotides to deoxynucleotides with either a Mn(III)2-tyrosyl radical (Y•) or Fe(III)2-Y• cofactor in the NrdF subunit. Whereas self-assemble from Fe(II)2-NrdF and O2, activation Mn(II)2-NrdF requires reduced flavoprotein, NrdI, proposed form oxidant for assembly by O2. crystal structures reported here E. reveal different coordination environments, suggesting distinct initial binding sites oxidants during...

Ribonucleotide reductases (RNRs) are a diverse family of enzymes that alone capable generating 2'-deoxynucleotides de novo and thus critical in DNA biosynthesis repair. The nucleotide reduction reaction all RNRs requires the generation transient active site thiyl radical, class I RNRs, this process involves long-range radical transfer between two subunits, α β. Because subunit association, an atomic resolution structure α2β2 RNR complex has been elusive. We used doubly substituted β2,...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStereochemical studies of the .beta.-elimination reactions at aldehydic abasic sites in DNA: endonuclease III from Escherichia coli, sodium hydroxide, and Lys-Trp-LysAbhijit Mazumder, John A. Gerlt, Michael J. Absalon, JoAnne Stubbe, Richard P. Cunningham, Jane Withka, Philip H. BoltonCite this: Biochemistry 1991, 30, 4, 1119–1126Publication Date (Print):January 1, 1991Publication History Published online1 May 2002Published inissue 1 January...

Disulfides are involved in a broad range of radical-based synthetic organic and biochemical transformations. In particular, the reduction disulfide to corresponding radical anion, followed by S-S bond cleavage yield thiyl thiolate anion plays critical roles photoredox transformations conjunction with proton donor, mediates enzymatic synthesis deoxynucleotides from nucleotides within active site enzyme, ribonucleotide reductase (RNR). To gain fundamental thermodynamic insight into these...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTN5-Carboxyaminoimidazole Ribonucleotide: Evidence for a New Intermediate and Two Enzymic Activities in the de Novo Purine Biosynthetic Pathway of Escherichia coliErnest J. Mueller, Erik Meyer, Johannes Rudolph, V. Jo Davisson, JoAnne StubbeCite this: Biochemistry 1994, 33, 8, 2269–2278Publication Date (Print):March 1, 1994Publication History Published online1 May 2002Published inissue 1 March...

A 3" ribonucleoside diphosphate reductase by 2"ClUDP abstraction of ketone intermediate could also be generated upon inactivation 1'-H atom 2"ClUDP.Results reported in this communication eliminate as a viable alternative.

Ribonucleotide reductases (RNRs) convert ribonucleotides into deoxyribonucleotides, a reaction essential for DNA replication and repair. Human RNR requires two subunits activity, the α subunit contains active site, β houses radical cofactor. Here, we present 3.3-Å resolution structure by cryo-electron microscopy (EM) of dATP-inhibited state human RNR. This structure, which was determined in presence substrate CDP allosteric regulators ATP dATP, has three α2 units arranged an α6 ring. At...

Radicals in biology, once thought to all be bad actors, are now known play a central role many enzymatic reactions. Of the radical-based enzymes, ribonucleotide reductases (RNRs) pre-eminent as they essential biology of organisms by providing building blocks and controlling fidelity DNA replication repair. Intense examination RNRs has led development new tools guiding framework for study radicals pointing way future frontiers radical enzymology.

Ribonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides to deoxyribonucleotides, thereby playing a key role in DNA replication and repair. Escherichia coli class Ia RNR is an α2β2 enzyme complex that uses reversible multistep radical transfer (RT) over 32 Å across its two subunits, α β, initiate, using metallo-cofactor β2, nucleotide α2. Each step proposed involve distinct proton-coupled electron-transfer (PCET) process. An unresolved RT involving Y356(β) Y731(α) α/β...

Escherichia coli ribonucleotide reductase (RNR) catalyzes the conversion of nucleoside diphosphates to deoxynucleoside diphosphates. The enzyme is composed two subunits: R1 and R2. contains active site for nucleotide reduction allosteric effector sites that regulate specificity turnover rate. R2 diferric-tyrosyl (Y•) radical cofactor initiates by a putative long-range proton-coupled electron transfer (PCET) pathway over 35 Å. This thought involve specific amino acid intermediates (Y122 W48...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInvestigation of the Mechanism Phosphoribosylamine Transfer from Glutamine Phosphoribosylpyrophosphate Amidotransferase to Glycinamide Ribonucleotide SynthetaseJ. Rudolph and J. StubbeCite this: Biochemistry 1995, 34, 7, 2241–2250Publication Date (Print):February 12, 1995Publication History Published online1 May 2002Published inissue 12 February 1995https://pubs.acs.org/doi/10.1021/bi00007a019https://doi.org/10.1021/bi00007a019research-articleACS...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIdentification of the alkaline-labile product accompanying cytosine release during bleomycin-mediated degradation d(CGCGCG)L. Rabow, J. Stubbe, W. Kozarich, and A. GerltCite this: Am. Chem. Soc. 1986, 108, 22, 7130–7131Publication Date (Print):October 1, 1986Publication History Published online1 May 2002Published inissue 1 October 1986https://pubs.acs.org/doi/10.1021/ja00282a063https://doi.org/10.1021/ja00282a063research-articleACS...

Streptococcus sanguinis is a causative agent of infective endocarditis. Deletion SsaB, manganese transporter, drastically reduces S. virulence. Many pathogenic organisms require class Ib ribonucleotide reductase (RNR) to catalyze the conversion nucleotides deoxynucleotides under aerobic conditions, and recent studies demonstrate that this enzyme uses dimanganese-tyrosyl radical (MnIII2-Y•) cofactor in vivo. The proteins required for reduction (NrdE NrdF, α β subunits RNR; NrdH TrxR,...

Ribonucleotide reductases (RNR) catalyze the reduction of nucleotides to deoxynucleotides through a mechanism involving an essential cysteine based thiyl radical. In E. coli class 1a RNR radical (C439•) is transient species generated by transfer (RT) from stable diferric-tyrosyl cofactor located >35 Å away across α2:β2 subunit interface. RT facilitated sequential proton-coupled electron (PCET) steps along pathway redox active amino acids (Y122β ↔ [W48β?] Y356β Y731α Y730α C439α). The mutant...

A new conformation of the<italic>E. coli</italic>RNR pathway residue 731 was trapped during long-range radical transfer across the αβ subunit interface.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanism of inactivation Escherichia coli and Lactobacillus leichmannii ribonucleotide reductases by 2'-chloro-2'-deoxynucleotides: evidence for generation 2-methylene-3(2H)-furanoneG. Harris, M. Ator, J. StubbeCite this: Biochemistry 1984, 23, 22, 5214–5225Publication Date (Print):October 1, 1984Publication History Published online1 May 2002Published inissue 1 October...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTProducts of the inactivation ribonucleoside diphosphate reductase from Escherichia coli with 2'-azido-2'-deoxyuridine 5'-diphosphateScott P. Salowe, Mark A. Ator, and JoAnne StubbeCite this: Biochemistry 1987, 26, 12, 3408–3416Publication Date (Print):June 16, 1987Publication History Published online1 May 2002Published inissue 16 June 1987https://pubs.acs.org/doi/10.1021/bi00386a024https://doi.org/10.1021/bi00386a024research-articleACS...

Photochemical ribonucleotide reductases (photoRNRs) are developed for the generation and transport of amino acid radicals by proton-coupled electron transfer (PCET) in this enzyme. The β2 subunit has been replaced with [Re]-3,5-F2Y-R2C19 peptide, which substitutes 3,5-F2Y Y at "position 356" contains Re(bpy)(CO)3CN ([Re]) photochemical radical generator. Excitation peptide 355 nm light produces [Re]0-3,5-F2Y· charge-separated state within nanosecond laser pulse, as characterized transient...

Redox-active tyrosines (Ys) play essential roles in enzymes involved primary metabolism including energy transduction and deoxynucleotide production catalyzed by ribonucleotide reductases (RNRs). Thermodynamic characterization of Ys solution proteins remains a challenge due to the high reduction potentials reactive nature radical state. The structurally characterized α3Y model protein has allowed first determination formal (E°′) for Y residing within (Berry, B. W.; Martı́nez-Rivera, M. C.;...