G04SecL04Tpc1: Difference between revisions

Although the exact mechanism of the bacterial effect of OspB and Fab H6831 complex is not know there are several hypotheses on how bacteria lysis occurs. One such hypothesis is that bacteria lysis is the direct result of oxidative reaction of singlet oxygen and water to yield hydrogen peroxide, ozone, and hydroxide radicals (Becker et al. 2005). Experiments done by Jorge Nieva and Paul Wentworth Jr of The Scripps Research Institute describe this reaction further. They suggest that this antibody-catalyzed water oxidation pathway is a property of nearly all antibodies and is similar to phagocytosis and that this may prove to be an important defense of the immune system.  However, in order for phagocytosis to occur the immune system must use a complement indirect cascade initiating a membrane attack complex (Connolly and Benach 2005). In the experiments by Nieva and Wentworth they provide evidence that this oxidative reaction is independent of this compliment system. They believe that singlet oxygen acts as the substrate and binds to binding sites within the outer surface protein folds (Nieva and Wentworth 2004). A singlet oxygen acts a nucleophile and attacks one water molecule to form the dihydrogentrioxide (H₂O₃) intermediate which then reacts to form hydrogen peroxide (H₂O₂) which when given an oxygen source proves to be bactericidal. Catalase prevents the reaction of hydrogen peroxide and ozone that produces hydroxide radicals which is the potential antibacterial agent (Nieva and Wentworth 2004). This oxidation reaction leads to damage in the cell wall and plasma membrance which leads to lysis of the cell which was observed through observation under an electron microscope (Nieva and Wentworth 2004). Because B. burgdorferi survives best in environments with limited oxygen and its genome does not encode for catalase it may be vulnerable to this oxidative reaction (Becker et al. 2005).