The present dissertation is focused on the phylogenetic, biochemical, structural and physiological analysis of the hydratases from Streptococcus pyogenes M49 and Lactobacillus acidophilus NCFM. These hydratases belong to myosin cross-reactive antigen (MCRA) protein family for which knowledge on the biochemical and physiological function is scarce. This study provides the first line of evidences on biological significance of this protein family as ubiquitous bacterial enzymes which metabolize highly toxic unsaturated fatty acids to their less toxic and more soluble hydroxy derivatives. Determined in this work de novo crystal structure of Lactobacillus acidophilus NCFM hydratase allows to classify the hydratases to the family of flavin containing amine oxidoreductases and establishes a framework for further biochemical and structural analysis of the rest MCRAs from the pathogenic and commensal bacterial species.weiterlesen