The prototypic class Ia ribonucleotide reductase from Escherichia coli: still surprising after all these years

Brignole, Edward J.; Ando, Nozomi; Zimanyi, Christina M.; Drennan, Catherine L.

doi:10.1042/bst20120081

Cited by 14 publications

(19 citation statements)

References 52 publications

(102 reference statements)

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“…TrxA also operates through a Cys-X-X-Cys motif and assists the Dsb system and ribonucleotide reductase [68]. Still, a trxA mutant of S .…”

Section: Thiol Chemistrymentioning

confidence: 99%

Salmonella and Reactive Oxygen Species: A Love-Hate Relationship

Rhen¹

2019

J Innate Immun

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Salmonella enterica represents an enterobacterial species including numerous serovars that cause infections at, or initiated at, the intestinal epithelium. Many serovars also act as facultative intracellular pathogens with a tropism for phagocytic cells. These bacteria not only survive in phagocytes but also undergo de facto replication therein. Phagocytes, through the activities of phagocyte NADPH-dependent oxidase and inducible nitric oxide synthase, are very proficient in converting molecular oxygen to reactive oxygen (ROS) and nitrogen species (RNS). These compounds represent highly efficient effectors of the innate immune defense. Salmonella is by no means resistant to these effectors, which may stand in contrast to the host niches chosen. To cope with this paradox, these bacteria rely on an array of detoxification and repair systems. Combination these systems allows for a high enough tolerance to ROS and RNS to enable establishment of infection. In addition, salmonella possesses protein factors that have the potential to dampen the infection-associated inflammation, which evidently results in a reduced exposure to ROS and RNS. This review attempts to summarize the activities and strategies by which salmonella tries to cope with ROS and RNS and how the bacterium can make use of these innate defense factors.

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“…TrxA also operates through a Cys-X-X-Cys motif and assists the Dsb system and ribonucleotide reductase [68]. Still, a trxA mutant of S .…”

Section: Thiol Chemistrymentioning

confidence: 99%

Salmonella and Reactive Oxygen Species: A Love-Hate Relationship

Rhen¹

2019

J Innate Immun

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“…The synthesis of dNTPs starts with the reduction of ribonucleoside diphosphates (rNDPs) to the corresponding dNDPs by ribonucleoside diphosphate reductase, an allosteric enzyme whose regulation ensures a proper balance of the 4 dNDPs [1,2]. Subsequently, the nonspecific action of nucleoside diphosphate kinase (NdpK) yields dNTPs at the expense of ATP and dNDPs [3–5].…”

Section: Introductionmentioning

confidence: 99%

A continuous spectrophotometric enzyme-coupled assay for deoxynucleoside triphosphate triphosphohydrolases

Singh

Schaaper

Hochkoeppler

2016

Analytical Biochemistry

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We describe here a continuous, spectrophotometric, enzyme-coupled assay useful to monitor reactions catalyzed by nucleoside triphosphohydrolases. In particular, using Escherichia coli deoxynucleoside triphosphohydrolase (Dgt), which hydrolyzes dGTP to deoxyguanosine and tripolyphosphate (PPPi), as the enzyme to be tested, we devised a procedure relying on purine nucleoside phosphorylase (PNPase) and xanthine oxidase (XOD) as the auxiliary enzymes. The deoxyguanosine released by Dgt can indeed be conveniently subjected to phosphorolysis by PNPase, yielding deoxyribose-1-phosphate and guanine, which, in turn, can be oxidized to 8-oxoguanine by XOD. By this means, it was possible to continuously detect Dgt activity at 297 nm, at which wavelength the difference between the molar extinction coefficients of 8-oxoguanine (8,000 M−1cm−1) and guanine (1,090 M−1cm−1) is maximal. The initial velocities of Dgt-catalyzed reactions were then determined in parallel with the enzyme-coupled assay and with a discontinuous HPLC method able to selectively detect deoxyguanosine. Under appropriate conditions of excess of auxiliary enzymes, the activities determined with our continuous enzyme-coupled assay were quantitatively comparable with those observed with the HPLC method. Moreover, the enzyme-coupled assay proved to be more sensitive than the chromatographic procedure, permitting reliable detection of Dgt activity at low dGTP substrate concentrations.

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“…In these enzymes, the metal cofactor is located in the R2 subunit, whereas the R1 subunit houses the active site of ribonucleotide reduction. In the classical R2 of Escherichia coli class-Ia RNR, two iron atoms form the cofactor, which are bound to the protein by the amino acid side chains of two histidine residues, three glutamates, and one aspartate, in a highly conserved binding motif (10,11).…”

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confidence: 99%

Rapid X-ray Photoreduction of Dimetal-Oxygen Cofactors in Ribonucleotide Reductase

Sigfridsson

Chernev

Leidel

et al. 2013

Journal of Biological Chemistry

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Background: Typical FeFe and MnFe cofactors bind to numerous enzymes such as ribonucleotide reductases. Crystallographic data suggest x-ray photoreduction (XPR) effects. Results: Rapid XPR-induced cofactor changes were monitored using time-resolved x-ray absorption spectroscopy. Conclusion: The XPR-induced cofactor states differ significantly from the native configurations, but comply with crystallographic structures. Significance: Structure determination for high-valent dimetal-oxygen cofactors requires free electron-laser protein crystallography combined with x-ray spectroscopy.

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The prototypic class Ia ribonucleotide reductase from Escherichia coli: still surprising after all these years

Cited by 14 publications

References 52 publications

<b><i>Salmonella</i></b> and Reactive Oxygen Species: A Love-Hate Relationship

<b><i>Salmonella</i></b> and Reactive Oxygen Species: A Love-Hate Relationship

A continuous spectrophotometric enzyme-coupled assay for deoxynucleoside triphosphate triphosphohydrolases

Rapid X-ray Photoreduction of Dimetal-Oxygen Cofactors in Ribonucleotide Reductase

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