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

Pau Arroyo Mañez, Changyuan Lu, Leonardo Boechi, Marcelo A. Martí, Mark Shepherd, Jayne Louise Wilson, Robert K. Poole, F. Javier Luque, Syun Ru Yeh, Darío A. Estrin

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19 Scopus citations

Abstract

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 G8WF mutant of Ctb and employed state-of-the-art computer simulation methods to investigate the properties of the O2 adduct of the G8 WF mutant, with respect to those of the wild-type protein and the previously studied E7HL and/or B10YF 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.

Original languageEnglish (US)
Pages (from-to)3946-3956
Number of pages11
JournalBiochemistry
Volume50
Issue number19
DOIs
StatePublished - May 17 2011

ASJC Scopus subject areas

  • Biochemistry

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    Arroyo Mañez, P., Lu, C., Boechi, L., Martí, M. A., Shepherd, M., Wilson, J. L., Poole, R. K., Luque, F. J., Yeh, S. R., & Estrin, D. A. (2011). Role of the distal hydrogen-bonding network in regulating oxygen affinity in the truncated hemoglobin III from campylobacter jejuni. Biochemistry, 50(19), 3946-3956. https://doi.org/10.1021/bi101137n