Reduction of Ribonucleotides

Thelander, Lars; Reichard, Peter

doi:10.1146/annurev.bi.48.070179.001025

Cited by 1,124 publications

(602 citation statements)

References 53 publications

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“…RNRs are a major site of regulation for the control of these pools (2,62). The common features of RNR regulation are the allosteric effectors that control, in part, the activity and substrate specificity and transcription factors that control the mRNA levels of the subunits as a function of the cell cycle (24,(63)(64)(65)(66). In eukaryotic systems, a third common regulatory mechanism involves sequestration of the subunits in different compartments within the cell (46,67,68).…”

Section: Discussionmentioning

confidence: 99%

Determination of the in Vivo Stoichiometry of Tyrosyl Radical per ββ‘ in Saccharomyces cerevisiae Ribonucleotide Reductase

et al. 2006

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The class I ribonucleotide reductases catalyze the conversion of nucleotides to deoxynucleotides and are composed of two subunits: R1 and R2. R1 contains the site for nucleotide reduction and the sites that control substrate specificity and the rate of reduction. R2 houses the essential diferric-tyrosyl radical (Y • ) cofactor. In Saccharomyces cerevisiae, two R1s, α n and , have been identified, while R2 is a heterodimer (ββ′). β′ cannot bind iron and generate the Y • ; consequently, the maximum amount of Y • per ββ′ is 1. To determine the cofactor stoichiometry in vivo, a FLAGtagged β ( FLAG β) was constructed and integrated into the genome of Y300 (MHY343). This strain facilitated the rapid isolation of endogenous levels of FLAG ββ′ by immunoaffinity chromatography, which was found to have 0.45 ± 0.08 Y • / FLAG ββ′ and a specific activity of 2.3 ± 0.5 μmol min −1 mg −1 . FLAG ββ′ isolated from MMS-treated MHY343 cells or cells containing a deletion of the transcriptional repressor gene CRT1 also gave a Y • / FLAG ββ′ ratio of 0.5. To determine the Y • /ββ′ ratio without R2 isolation, whole cell EPR and quantitative Western blots of β were performed using different strains and growth conditions. The wild-type (wt) strains gave a Y • /ββ′ ratio of 0.83-0.89. The same strains either treated with MMS or containing a crt1Δ gave ratios between 0.49 and 0.72. Nucleotide reduction assays and quantitative Western blots from the same strains provided an independent measure and confirmation of the Y • /ββ′ ratios. Thus, under normal growth conditions, the cell assembles stoichiometric amounts of Y • and modulation of Y • concentration is not involved in the regulation of RNR activity.

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Section: Discussionmentioning

confidence: 99%

Determination of the in Vivo Stoichiometry of Tyrosyl Radical per ββ‘ in Saccharomyces cerevisiae Ribonucleotide Reductase

et al. 2006

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“…This reaction is rate limiting in the production of 2'-deoxyribonucleoside-5'-triphosphates (dNTPs), which are essential for the de novo synthesis of DNA. 3 Gemcitabine diphosphate (dFdCDP) binds to the large subunit M1 of RR (RRM1) and inhibits RR, thereby depleting the cellular deoxynucleotide (dNTP) pools. 4,5 RRM1 has been identified as the key molecule in determining the efficacy of gemcitabine.…”

Section: Introductionmentioning

confidence: 99%

Silencing of ribonucleotide reductase subunit M1 potentiates the antitumor activity of gemcitabine in resistant cancer cells

Wonganan

Chung

Zhu

et al. 2012

Cancer Biology & Therapy

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“…The tyrosyl radical exhibits a characteristic EPR doublet signal at g = 2.0047. The activity of RR is directly proportional to the amount of tyrosyl radical in protein R2 [1][2][3][4][5][6]. The three-dimensional crystal structure of *Corresponding author.…”

Section: Introductionmentioning

confidence: 99%

Reduction of the tyrosyl radical and the iron center in protein R2 of ribonucleotide reductase from mouse, herpes simplex virus and E. coli by p‐alkoxyphenols

et al. 1995

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The rate of reduction of the tyrosyl radical in the small subunit of ribonucleotide reductase (protein R2) from E. coli, mouse, and herpes simplex virus (HSV-2) by a series of p-alkoxyphenols with different alkyl chains, have been studied by stopped-flow UV-vis and stopped-flow EPR spectroscopy. The reduction and release of iron in R2 by the inhibitors was followed using bathophenanthroline as chelator of Fe 2+. p-Alkoxyphenols reduce the mouse R2 tyrosyl radical 1-2 orders of magnitude faster than the HSV-2 and E. coli radical. In contrast to E. coli, the iron center in R2 from mouse and HSV-2 is reduced by the inhibitors. For mouse R2, the rate of reduction of the tyrosyl radical increases in parallel with increasing alkyl chain length of the inhibitor, an observation which may be important for the design of new antiproliferative drugs.

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Reduction of Ribonucleotides

Cited by 1,124 publications

References 53 publications

Determination of the in Vivo Stoichiometry of Tyrosyl Radical per ββ‘ in Saccharomyces cerevisiae Ribonucleotide Reductase

Determination of the in Vivo Stoichiometry of Tyrosyl Radical per ββ‘ in Saccharomyces cerevisiae Ribonucleotide Reductase

Silencing of ribonucleotide reductase subunit M1 potentiates the antitumor activity of gemcitabine in resistant cancer cells

Reduction of the tyrosyl radical and the iron center in protein R2 of ribonucleotide reductase from mouse, herpes simplex virus and E. coli by p‐alkoxyphenols

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