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Updated: Jun 2, 2026

Anaerobic Protein Purification and Kinetic Analysis via Oxygen Electrode for Studying DesB Dioxygenase Activity and Inhibition
08:31

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Role of the distal hydrogen-bonding network in regulating oxygen affinity in the truncated hemoglobin III from

Pau Arroyo Mañez1, Changyuan Lu, Leonardo Boechi

  • 1Departamento de Química Inorgánica, Analítica, y Química Fisica, INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Ciudad Universitaria , Buenos Aires, Argentina.

Biochemistry
|April 12, 2011
PubMed

Oxygen affinity in heme-containing proteins is determined by a number of factors, such as the nature and conformation of the distal residues that stabilize the heme bound-oxygen via hydrogen-bonding interactions. The truncated hemoglobin III from Campylobacter jejuni (Ctb) contains three potential hydrogen-bond donors in the distal site: TyrB10, TrpG8, and HisE7. Previous studies suggested that Ctb exhibits an extremely slow oxygen dissociation rate due to an interlaced hydrogen-bonding network involving the three distal residues. Here we have studied the structural and kinetic properties of the G8(WF) mutant of Ctb and employed state-of-the-art computer simulation methods to investigate the properties of the O(2) adduct of the G8(WF) mutant, with respect to those of the wild-type protein and the previously studied E7(HL) and/or B10(YF) mutants. Our data indicate that the unique oxygen binding properties of Ctb are determined by the interplay of hydrogen-bonding interactions between the heme-bound ligand and the surrounding TyrB10, TrpG8, and HisE7 residues.

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