The single-domain globin from the pathogenic bacterium Campylobacter jejuni: Novel D-helix conformation, proximal hydrogen bonding that influences ligand binding, and peroxidase-like redox properties

Mark Shepherd, Vladimir Barynin, Changyuan Lu, Paul V. Bernhardt, Guanghui Wu, Syun-Ru Yeh, Tsuyoshi Egawa, Svetlana E. Sedelnikova, David W. Rice, Jayne Louise Wilson, Robert K. Poole

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The food-borne pathogen Campylobacter jejuni possesses a single-domain globin (Cgb) whose role in detoxifying nitric oxide has been unequivocally demonstrated through genetic and molecular approaches. The x-ray structure of cyanidebound Cgb has been solved to a resolution of 1.35 Å. The overall fold is a classic three-on-three α-helical globin fold, similar to that of myoglobin and Vgb from Vitreoscilla stercoraria. However, the Dregion (defined according to the standard globin fold nomenclature) of Cgb adopts a highly ordered α-helical conformation unlike any previously characterized members of this globin family, and the GlnE7 residue has an unexpected role in modulating the interaction between the ligand and the TyrB10 residue. The proximal hydrogen bonding network in Cgb demonstrates that the heme cofactor is ligated by an imidazolate, a characteristic of peroxidase-like proteins. Mutation of either proximal hydrogen-bonding residue (GluH23 or TyrG5) results in the loss of the high frequency νFe-His stretching mode (251 cm-1), indicating that both residues are important for maintaining the anionic character of the proximal histidine ligand. Cyanide binding kinetics for these proximal mutants demonstrate for the first time that proximal hydrogen bonding in globins can modulate ligand binding kinetics at the distal site. A low redox midpoint for the ferrous/ferric couple (-134mV versus normal hydrogen electrode at pH 7) is consistent with the peroxidase-like character of the Cgb active site. These data provide a new insight into the mechanism via which Campylobacter may survive host-derived nitrosative stress.

Original languageEnglish (US)
Pages (from-to)12747-12754
Number of pages8
JournalJournal of Biological Chemistry
Volume285
Issue number17
DOIs
StatePublished - Apr 23 2010

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Campylobacter jejuni
Globins
Hydrogen Bonding
Peroxidase
Oxidation-Reduction
Conformations
Bacteria
Hydrogen bonds
Ligands
Vitreoscilla
Kinetics
Campylobacter
Myoglobin
Cyanides
Pathogens
Terminology
Heme
Histidine
Stretching
Molecular Biology

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

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The single-domain globin from the pathogenic bacterium Campylobacter jejuni : Novel D-helix conformation, proximal hydrogen bonding that influences ligand binding, and peroxidase-like redox properties. / Shepherd, Mark; Barynin, Vladimir; Lu, Changyuan; Bernhardt, Paul V.; Wu, Guanghui; Yeh, Syun-Ru; Egawa, Tsuyoshi; Sedelnikova, Svetlana E.; Rice, David W.; Wilson, Jayne Louise; Poole, Robert K.

In: Journal of Biological Chemistry, Vol. 285, No. 17, 23.04.2010, p. 12747-12754.

Research output: Contribution to journalArticle

Shepherd, Mark ; Barynin, Vladimir ; Lu, Changyuan ; Bernhardt, Paul V. ; Wu, Guanghui ; Yeh, Syun-Ru ; Egawa, Tsuyoshi ; Sedelnikova, Svetlana E. ; Rice, David W. ; Wilson, Jayne Louise ; Poole, Robert K. / The single-domain globin from the pathogenic bacterium Campylobacter jejuni : Novel D-helix conformation, proximal hydrogen bonding that influences ligand binding, and peroxidase-like redox properties. In: Journal of Biological Chemistry. 2010 ; Vol. 285, No. 17. pp. 12747-12754.
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abstract = "The food-borne pathogen Campylobacter jejuni possesses a single-domain globin (Cgb) whose role in detoxifying nitric oxide has been unequivocally demonstrated through genetic and molecular approaches. The x-ray structure of cyanidebound Cgb has been solved to a resolution of 1.35 {\AA}. The overall fold is a classic three-on-three α-helical globin fold, similar to that of myoglobin and Vgb from Vitreoscilla stercoraria. However, the Dregion (defined according to the standard globin fold nomenclature) of Cgb adopts a highly ordered α-helical conformation unlike any previously characterized members of this globin family, and the GlnE7 residue has an unexpected role in modulating the interaction between the ligand and the TyrB10 residue. The proximal hydrogen bonding network in Cgb demonstrates that the heme cofactor is ligated by an imidazolate, a characteristic of peroxidase-like proteins. Mutation of either proximal hydrogen-bonding residue (GluH23 or TyrG5) results in the loss of the high frequency νFe-His stretching mode (251 cm-1), indicating that both residues are important for maintaining the anionic character of the proximal histidine ligand. Cyanide binding kinetics for these proximal mutants demonstrate for the first time that proximal hydrogen bonding in globins can modulate ligand binding kinetics at the distal site. A low redox midpoint for the ferrous/ferric couple (-134mV versus normal hydrogen electrode at pH 7) is consistent with the peroxidase-like character of the Cgb active site. These data provide a new insight into the mechanism via which Campylobacter may survive host-derived nitrosative stress.",
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T1 - The single-domain globin from the pathogenic bacterium Campylobacter jejuni

T2 - Novel D-helix conformation, proximal hydrogen bonding that influences ligand binding, and peroxidase-like redox properties

AU - Shepherd, Mark

AU - Barynin, Vladimir

AU - Lu, Changyuan

AU - Bernhardt, Paul V.

AU - Wu, Guanghui

AU - Yeh, Syun-Ru

AU - Egawa, Tsuyoshi

AU - Sedelnikova, Svetlana E.

AU - Rice, David W.

AU - Wilson, Jayne Louise

AU - Poole, Robert K.

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N2 - The food-borne pathogen Campylobacter jejuni possesses a single-domain globin (Cgb) whose role in detoxifying nitric oxide has been unequivocally demonstrated through genetic and molecular approaches. The x-ray structure of cyanidebound Cgb has been solved to a resolution of 1.35 Å. The overall fold is a classic three-on-three α-helical globin fold, similar to that of myoglobin and Vgb from Vitreoscilla stercoraria. However, the Dregion (defined according to the standard globin fold nomenclature) of Cgb adopts a highly ordered α-helical conformation unlike any previously characterized members of this globin family, and the GlnE7 residue has an unexpected role in modulating the interaction between the ligand and the TyrB10 residue. The proximal hydrogen bonding network in Cgb demonstrates that the heme cofactor is ligated by an imidazolate, a characteristic of peroxidase-like proteins. Mutation of either proximal hydrogen-bonding residue (GluH23 or TyrG5) results in the loss of the high frequency νFe-His stretching mode (251 cm-1), indicating that both residues are important for maintaining the anionic character of the proximal histidine ligand. Cyanide binding kinetics for these proximal mutants demonstrate for the first time that proximal hydrogen bonding in globins can modulate ligand binding kinetics at the distal site. A low redox midpoint for the ferrous/ferric couple (-134mV versus normal hydrogen electrode at pH 7) is consistent with the peroxidase-like character of the Cgb active site. These data provide a new insight into the mechanism via which Campylobacter may survive host-derived nitrosative stress.

AB - The food-borne pathogen Campylobacter jejuni possesses a single-domain globin (Cgb) whose role in detoxifying nitric oxide has been unequivocally demonstrated through genetic and molecular approaches. The x-ray structure of cyanidebound Cgb has been solved to a resolution of 1.35 Å. The overall fold is a classic three-on-three α-helical globin fold, similar to that of myoglobin and Vgb from Vitreoscilla stercoraria. However, the Dregion (defined according to the standard globin fold nomenclature) of Cgb adopts a highly ordered α-helical conformation unlike any previously characterized members of this globin family, and the GlnE7 residue has an unexpected role in modulating the interaction between the ligand and the TyrB10 residue. The proximal hydrogen bonding network in Cgb demonstrates that the heme cofactor is ligated by an imidazolate, a characteristic of peroxidase-like proteins. Mutation of either proximal hydrogen-bonding residue (GluH23 or TyrG5) results in the loss of the high frequency νFe-His stretching mode (251 cm-1), indicating that both residues are important for maintaining the anionic character of the proximal histidine ligand. Cyanide binding kinetics for these proximal mutants demonstrate for the first time that proximal hydrogen bonding in globins can modulate ligand binding kinetics at the distal site. A low redox midpoint for the ferrous/ferric couple (-134mV versus normal hydrogen electrode at pH 7) is consistent with the peroxidase-like character of the Cgb active site. These data provide a new insight into the mechanism via which Campylobacter may survive host-derived nitrosative stress.

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