Ligand binding properties of bacterial hemoglobins and flavohemoglobins

Judith Farrés, Markus P. Rechsteiner, Susanna Herold, Alexander D. Frey, Pauli T. Kallio*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

34 Citations (Scopus)

Abstract

Bacterial hemoglobins and flavohemoglobins share a common globin fold but differ otherwise in structural and functional aspects. The bases of these differences were investigated through kinetic studies on oxygen, carbon monoxide, and nitric oxide binding. The novel bacterial hemoglobins from Clostridium perfringens and Campylobacter jejuni and the flavohemoglobins from Bacillus subtilis and Salmonella enterica serovar Typhi have been analyzed. Examination of the biochemical and ligand binding properties of these proteins shows a clear distinction between the two groups. Flavohemoglobins show a much greater tendency to autoxidation compared to bacterial hemoglobins. The differences in affinity for oxygen, carbon monoxide, and nitric oxide between bacterial hemoglobins and flavohemoglobins are mainly due to differences in the association rate constants. The second-order rate constants for oxygen and carbon monoxide binding to bacterial hemoglobins are severalfold higher than those for flavohemoglobins. A similar trend is observed for NO association with the oxidized iron(III) form of the proteins. No major differences are observed among the values obtained for the dissociation rate constants for the two groups of bacterial proteins studied, and these constants are all rather similar to those for myoglobin. Taken together, our data suggest that differences exist between the mechanisms of ligand binding to bacterial hemoglobins and flavohemoglobins, suggesting different functions in the cell.

Original languageEnglish
Pages (from-to)4125-4134
Number of pages10
JournalBiochemistry
Volume44
Issue number10
DOIs
Publication statusPublished - 15 Feb 2005
MoE publication typeA1 Journal article-refereed

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