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, M, Barynin, V, Lu, CY, Bernhardt, PV, Wu, GH, Yeh, SR, Egawa, T, Sedelnikova, SE, Rice, DW, Wilson, JL and Poole, RK (2010) 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. Journal of Biological Chemistry, 285 17: 12747-12754. doi:10.1074/jbc.M109.084509

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Author Shepherd, M
Barynin, V
Lu, CY
Bernhardt, PV
Wu, GH
Yeh, SR
Egawa, T
Sedelnikova, SE
Rice, DW
Wilson, JL
Poole, RK
Title 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
Formatted title
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
Journal name Journal of Biological Chemistry   Check publisher's open access policy
ISSN 0021-9258
1083-351X
Publication date 2010-04-23
Sub-type Article (original research)
DOI 10.1074/jbc.M109.084509
Open Access Status File (Publisher version)
Volume 285
Issue 17
Start page 12747
End page 12754
Total pages 8
Place of publication Bethesda, MD, United States
Publisher American Society for Biochemistry and Molecular Biology
Collection year 2011
Language eng
Formatted 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. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.
Keyword Crystal-structure
Macromolecular structures
Distal heme pocket
Truncated hemoglobin
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Chemistry and Molecular Biosciences
 
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Created: Sun, 02 May 2010, 00:05:27 EST