Structural and functional properties of a truncated hemoglobin from a food-borne pathogen Campylobacter jejuni

Changyuan Lu, Tsuyoshi Egawa, Laura M. Wainwright, Robert K. Poole, Syun-Ru Yeh

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

Campylobacter jejuni contains two hemoglobins, Cgb and Ctb. Cgb has been suggested to perform an NO detoxification reaction to protect the bacterium against NO attack. On the other hand, the physiological function of Ctb, a class III truncated hemoglobin, remains unclear. By using CO as a structural probe, resonance Raman data show that the distal heme pocket of Ctb exhibits a positive electrostatic potential. In addition, two ligand-related vibrational modes, νFe-O2 and νO-O, were identified in the oxy derivative, with frequencies at 542 and 1132 cm-1, respectively, suggesting the presence of an intertwined H-bonding network surrounding the heme-bound ligand, which accounts for its unusually high oxygen affinity (222 μM-1). Mutagenesis studies of various distal mutants suggest that the heme-bound dioxygen is stabilized by H-bonds donated from the Tyr(B10) and Trp(G8) residues, which are highly conserved in the class III truncated hemoglobins; furthermore, an additional H-bond donated from the His(E7) to the Tyr(B10) further regulates these H-bonding interactions by restricting the conformational freedom of the phenolic side chain of the Tyr(B10). Taken together, the data suggest that it is the intricate balance of the H-bonding interactions that determines the unique ligand binding properties of Ctb. The extremely high oxygen affinity of Ctb makes it unlikely to function as an oxygen transporter; on the other hand, the distal heme environment of Ctb is surprisingly similar to that of cytochrome c peroxidase, suggesting a role of Ctb in performing a peroxidase or P450-type of oxygen chemistry.

Original languageEnglish (US)
Pages (from-to)13627-13636
Number of pages10
JournalJournal of Biological Chemistry
Volume282
Issue number18
DOIs
StatePublished - May 4 2007

Fingerprint

Truncated Hemoglobins
Campylobacter jejuni
Pathogens
Heme
Oxygen
Food
Ligands
Cytochrome-c Peroxidase
Detoxification
Mutagenesis
Carbon Monoxide
Static Electricity
Peroxidase
Electrostatics
Bacteria
Hemoglobins
Derivatives

ASJC Scopus subject areas

  • Biochemistry

Cite this

Structural and functional properties of a truncated hemoglobin from a food-borne pathogen Campylobacter jejuni. / Lu, Changyuan; Egawa, Tsuyoshi; Wainwright, Laura M.; Poole, Robert K.; Yeh, Syun-Ru.

In: Journal of Biological Chemistry, Vol. 282, No. 18, 04.05.2007, p. 13627-13636.

Research output: Contribution to journalArticle

Lu, Changyuan ; Egawa, Tsuyoshi ; Wainwright, Laura M. ; Poole, Robert K. ; Yeh, Syun-Ru. / Structural and functional properties of a truncated hemoglobin from a food-borne pathogen Campylobacter jejuni. In: Journal of Biological Chemistry. 2007 ; Vol. 282, No. 18. pp. 13627-13636.
@article{449406d06e394bad9625c1cd0bf244f1,
title = "Structural and functional properties of a truncated hemoglobin from a food-borne pathogen Campylobacter jejuni",
abstract = "Campylobacter jejuni contains two hemoglobins, Cgb and Ctb. Cgb has been suggested to perform an NO detoxification reaction to protect the bacterium against NO attack. On the other hand, the physiological function of Ctb, a class III truncated hemoglobin, remains unclear. By using CO as a structural probe, resonance Raman data show that the distal heme pocket of Ctb exhibits a positive electrostatic potential. In addition, two ligand-related vibrational modes, νFe-O2 and νO-O, were identified in the oxy derivative, with frequencies at 542 and 1132 cm-1, respectively, suggesting the presence of an intertwined H-bonding network surrounding the heme-bound ligand, which accounts for its unusually high oxygen affinity (222 μM-1). Mutagenesis studies of various distal mutants suggest that the heme-bound dioxygen is stabilized by H-bonds donated from the Tyr(B10) and Trp(G8) residues, which are highly conserved in the class III truncated hemoglobins; furthermore, an additional H-bond donated from the His(E7) to the Tyr(B10) further regulates these H-bonding interactions by restricting the conformational freedom of the phenolic side chain of the Tyr(B10). Taken together, the data suggest that it is the intricate balance of the H-bonding interactions that determines the unique ligand binding properties of Ctb. The extremely high oxygen affinity of Ctb makes it unlikely to function as an oxygen transporter; on the other hand, the distal heme environment of Ctb is surprisingly similar to that of cytochrome c peroxidase, suggesting a role of Ctb in performing a peroxidase or P450-type of oxygen chemistry.",
author = "Changyuan Lu and Tsuyoshi Egawa and Wainwright, {Laura M.} and Poole, {Robert K.} and Syun-Ru Yeh",
year = "2007",
month = "5",
day = "4",
doi = "10.1074/jbc.M609397200",
language = "English (US)",
volume = "282",
pages = "13627--13636",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "18",

}

TY - JOUR

T1 - Structural and functional properties of a truncated hemoglobin from a food-borne pathogen Campylobacter jejuni

AU - Lu, Changyuan

AU - Egawa, Tsuyoshi

AU - Wainwright, Laura M.

AU - Poole, Robert K.

AU - Yeh, Syun-Ru

PY - 2007/5/4

Y1 - 2007/5/4

N2 - Campylobacter jejuni contains two hemoglobins, Cgb and Ctb. Cgb has been suggested to perform an NO detoxification reaction to protect the bacterium against NO attack. On the other hand, the physiological function of Ctb, a class III truncated hemoglobin, remains unclear. By using CO as a structural probe, resonance Raman data show that the distal heme pocket of Ctb exhibits a positive electrostatic potential. In addition, two ligand-related vibrational modes, νFe-O2 and νO-O, were identified in the oxy derivative, with frequencies at 542 and 1132 cm-1, respectively, suggesting the presence of an intertwined H-bonding network surrounding the heme-bound ligand, which accounts for its unusually high oxygen affinity (222 μM-1). Mutagenesis studies of various distal mutants suggest that the heme-bound dioxygen is stabilized by H-bonds donated from the Tyr(B10) and Trp(G8) residues, which are highly conserved in the class III truncated hemoglobins; furthermore, an additional H-bond donated from the His(E7) to the Tyr(B10) further regulates these H-bonding interactions by restricting the conformational freedom of the phenolic side chain of the Tyr(B10). Taken together, the data suggest that it is the intricate balance of the H-bonding interactions that determines the unique ligand binding properties of Ctb. The extremely high oxygen affinity of Ctb makes it unlikely to function as an oxygen transporter; on the other hand, the distal heme environment of Ctb is surprisingly similar to that of cytochrome c peroxidase, suggesting a role of Ctb in performing a peroxidase or P450-type of oxygen chemistry.

AB - Campylobacter jejuni contains two hemoglobins, Cgb and Ctb. Cgb has been suggested to perform an NO detoxification reaction to protect the bacterium against NO attack. On the other hand, the physiological function of Ctb, a class III truncated hemoglobin, remains unclear. By using CO as a structural probe, resonance Raman data show that the distal heme pocket of Ctb exhibits a positive electrostatic potential. In addition, two ligand-related vibrational modes, νFe-O2 and νO-O, were identified in the oxy derivative, with frequencies at 542 and 1132 cm-1, respectively, suggesting the presence of an intertwined H-bonding network surrounding the heme-bound ligand, which accounts for its unusually high oxygen affinity (222 μM-1). Mutagenesis studies of various distal mutants suggest that the heme-bound dioxygen is stabilized by H-bonds donated from the Tyr(B10) and Trp(G8) residues, which are highly conserved in the class III truncated hemoglobins; furthermore, an additional H-bond donated from the His(E7) to the Tyr(B10) further regulates these H-bonding interactions by restricting the conformational freedom of the phenolic side chain of the Tyr(B10). Taken together, the data suggest that it is the intricate balance of the H-bonding interactions that determines the unique ligand binding properties of Ctb. The extremely high oxygen affinity of Ctb makes it unlikely to function as an oxygen transporter; on the other hand, the distal heme environment of Ctb is surprisingly similar to that of cytochrome c peroxidase, suggesting a role of Ctb in performing a peroxidase or P450-type of oxygen chemistry.

UR - http://www.scopus.com/inward/record.url?scp=34249785140&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=34249785140&partnerID=8YFLogxK

U2 - 10.1074/jbc.M609397200

DO - 10.1074/jbc.M609397200

M3 - Article

C2 - 17339325

AN - SCOPUS:34249785140

VL - 282

SP - 13627

EP - 13636

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 18

ER -