Metalloenzymes in microbial defence mechanisms against oxygen and nitric oxide

Abstract

"Oxygen, nitric oxide and their derived species play key roles in life. Whereas O2 is essential in many organisms to survive, others use NO as defence mechanisms against pathogens. For example, the human immune system releases NO and H2O2, leading to the inhibition of multiple metabolic microbial processes. Flavodiiron proteins (FDPs) constitute a widespread family of enzymes present in all life domains with a crucial role in O2/ROS and/or NO detoxification, through the reduction of these species either to H2O or N2O, respectively. Therefore, flavodiiron proteins are key players in host-microbe interactions, from a host-pathogen strife viewpoint, and for survival of the human microbiota within challenging environments. (...) This thesis is focused on the study of FDPs mainly from human pathogens, in special Clostridia, the phylogenetic group with the larger diversity of FDPs’ classes and a widespread class of organisms among the human gut microbiome.(...)"