Direct Measurement of the Radical Translocation Distance in the Class i Ribonucleotide Reductase from Chlamydia trachomatis

Jovan Livada, Ryan J. Martinie, Laura M.K. Dassama, Carsten Krebs, Joseph M. Bollinger, Jr., Alexey Silakov

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Ribonucleotide reductases (RNRs) catalyze conversion of ribonucleotides to deoxyribonucleotides in all organisms via a free-radical mechanism that is essentially conserved. In class I RNRs, the reaction is initiated and terminated by radical translocation (RT) between the α and β subunits. In the class Ic RNR from Chlamydia trachomatis (Ct RNR), the initiating event converts the active S = 1 Mn(IV)/Fe(III) cofactor to the S = 1/2 Mn(III)/Fe(III) "RT-product"? form in the β subunit and generates a cysteinyl radical in the α active site. The radical can be trapped via the well-described decomposition reaction of the mechanism-based inactivator, 2′-azido-2′-deoxyuridine-5′-diphosphate, resulting in the generation of a long-lived, nitrogen-centered radical (N) in α. In this work, we have determined the distance between the Mn(III)/Fe(III) cofactor in β and N in α to be 43 ± 1 Å by using double electron-electron resonance experiments. This study provides the first structural data on the Ct RNR holoenzyme complex and the first direct experimental measurement of the inter-subunit RT distance in any class I RNR.

Original languageEnglish (US)
Pages (from-to)13777-13784
Number of pages8
JournalJournal of Physical Chemistry B
Volume119
Issue number43
DOIs
StatePublished - Oct 29 2015

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Ribonucleotide Reductases
Electron resonance
Deoxyribonucleotides
diphosphates
Ribonucleotides
Holoenzymes
Free radicals
organisms
free radicals
Free Radicals
Oxidoreductases
electrons
Nitrogen
Decomposition
decomposition
nitrogen
Electrons
products

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

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title = "Direct Measurement of the Radical Translocation Distance in the Class i Ribonucleotide Reductase from Chlamydia trachomatis",
abstract = "Ribonucleotide reductases (RNRs) catalyze conversion of ribonucleotides to deoxyribonucleotides in all organisms via a free-radical mechanism that is essentially conserved. In class I RNRs, the reaction is initiated and terminated by radical translocation (RT) between the α and β subunits. In the class Ic RNR from Chlamydia trachomatis (Ct RNR), the initiating event converts the active S = 1 Mn(IV)/Fe(III) cofactor to the S = 1/2 Mn(III)/Fe(III) {"}RT-product{"}? form in the β subunit and generates a cysteinyl radical in the α active site. The radical can be trapped via the well-described decomposition reaction of the mechanism-based inactivator, 2′-azido-2′-deoxyuridine-5′-diphosphate, resulting in the generation of a long-lived, nitrogen-centered radical (N•) in α. In this work, we have determined the distance between the Mn(III)/Fe(III) cofactor in β and N• in α to be 43 ± 1 {\AA} by using double electron-electron resonance experiments. This study provides the first structural data on the Ct RNR holoenzyme complex and the first direct experimental measurement of the inter-subunit RT distance in any class I RNR.",
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Direct Measurement of the Radical Translocation Distance in the Class i Ribonucleotide Reductase from Chlamydia trachomatis. / Livada, Jovan; Martinie, Ryan J.; Dassama, Laura M.K.; Krebs, Carsten; Bollinger, Jr., Joseph M.; Silakov, Alexey.

In: Journal of Physical Chemistry B, Vol. 119, No. 43, 29.10.2015, p. 13777-13784.

Research output: Contribution to journalArticle

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AU - Livada, Jovan

AU - Martinie, Ryan J.

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AU - Bollinger, Jr., Joseph M.

AU - Silakov, Alexey

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N2 - Ribonucleotide reductases (RNRs) catalyze conversion of ribonucleotides to deoxyribonucleotides in all organisms via a free-radical mechanism that is essentially conserved. In class I RNRs, the reaction is initiated and terminated by radical translocation (RT) between the α and β subunits. In the class Ic RNR from Chlamydia trachomatis (Ct RNR), the initiating event converts the active S = 1 Mn(IV)/Fe(III) cofactor to the S = 1/2 Mn(III)/Fe(III) "RT-product"? form in the β subunit and generates a cysteinyl radical in the α active site. The radical can be trapped via the well-described decomposition reaction of the mechanism-based inactivator, 2′-azido-2′-deoxyuridine-5′-diphosphate, resulting in the generation of a long-lived, nitrogen-centered radical (N•) in α. In this work, we have determined the distance between the Mn(III)/Fe(III) cofactor in β and N• in α to be 43 ± 1 Å by using double electron-electron resonance experiments. This study provides the first structural data on the Ct RNR holoenzyme complex and the first direct experimental measurement of the inter-subunit RT distance in any class I RNR.

AB - Ribonucleotide reductases (RNRs) catalyze conversion of ribonucleotides to deoxyribonucleotides in all organisms via a free-radical mechanism that is essentially conserved. In class I RNRs, the reaction is initiated and terminated by radical translocation (RT) between the α and β subunits. In the class Ic RNR from Chlamydia trachomatis (Ct RNR), the initiating event converts the active S = 1 Mn(IV)/Fe(III) cofactor to the S = 1/2 Mn(III)/Fe(III) "RT-product"? form in the β subunit and generates a cysteinyl radical in the α active site. The radical can be trapped via the well-described decomposition reaction of the mechanism-based inactivator, 2′-azido-2′-deoxyuridine-5′-diphosphate, resulting in the generation of a long-lived, nitrogen-centered radical (N•) in α. In this work, we have determined the distance between the Mn(III)/Fe(III) cofactor in β and N• in α to be 43 ± 1 Å by using double electron-electron resonance experiments. This study provides the first structural data on the Ct RNR holoenzyme complex and the first direct experimental measurement of the inter-subunit RT distance in any class I RNR.

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