Flavohemoglobin of Staphylococcus aureus.

Biotically, bacteria encounter nitrogen-reactive species in environments where denitrification occurs or when nitric oxide (NO) is generated by the mammal NO synthase, particularly during the infectious processes. In bacteria, flavohemoglobins have been shown to be one of the major systems responsible for the scavenging of these chemical species, either in aerobic or in anaerobic environments. Staphylococcus aureus, a pathogenic bacterium with high impact on human heath, also contains a gene encoding a homologue of a flavohemoprotein. The study of the recombinant protein and of the knockout mutant strain allowed us to conclude that, in spite of sharing similar physicochemical properties with the other known flavohemoglobins, the S. aureus flavohemoglobin requires microaerobic conditions to protect this bacterium from the nocive effects of the nitrosative stress.