doi: 10.1006/jmbi.1999.3448. the dimer interface; mutational analyses suggested that this metallic site contributes to protein stability, with implications for bacterial defense mechanisms. Biochemical and structural analyses educated us about electrostatic substrate guidance, dimer assembly, and an revealed C-terminal epitope in the NmSOD dimer. In contrast, the monomeric BaSOD structure offered insights for extending immunogenic peptide epitopes derived from the protein. These collective results reveal unique contributions of SOD to pathogenic virulence, refine predictive motifs for distinguishing SOD classes, and suggest general focuses on for antibacterial immune responses. The recognized functional contributions, motifs, and focuses on distinguishing bacterial and eukaryotic SOD assemblies presented here provide a basis for efforts to develop SOD-specific inhibitors of or vaccines against these harmful pathogens. IMPORTANCE By protecting microbes against reactive oxygen insults, SODs aid survival of many bacteria within their hosts. Despite the ubiquity and conservation of these key enzymes, notable species-specific variations relevant to pathogenesis remain undefined. To probe mechanisms that govern the functioning of and SODs, we used X-ray constructions, enzymology, modeling, and murine illness experiments. We recognized virulence determinants Rabbit Polyclonal to OR51G2 common to the two homologs, assembly variations, and a unique metallic reservoir within meningococcal SOD that stabilizes the enzyme and may provide a safeguard against copper toxicity. The insights reported here provide a rationale and a basis for SOD-specific drug design and an extension of immunogen design BCR-ABL-IN-1 to target two important pathogens that continue to pose global health threats. Intro Superoxide dismutases are expert scavengers of reactive oxygen species (ROS), which are inevitable byproducts of aerobic existence. ROS, such as superoxide anion (O2?), H2O2, and HO?, play essential and varied tasks in biological processes ranging from ageing and oncogenesis to pathogenesis and antibiotic action (1,C4). ROS act as signals at low levels but as cytotoxins at higher levels (3, 5,C8), so virtually all aerobic (and many anaerobic) organisms possess developed defenses for ROS detoxification. The superoxide dismutase enzymes, which catalyze disproportionation of O2? radicals, are one such important antioxidant defense (9, 10). Three structurally unique families use alternate oxidation and reduction of active-site metallic ion cofactors (11) (Mn/Fe, Ni, or Cu coupled to Zn) to protect different subcellular compartments (10). Ubiquitous Cu,Zn superoxide dismutase (SOD) family members show a Greek-key -barrel collapse (12, 13) and may exist as monomers, dimers, or tetramers of unique assemblies, depending on the particular enzyme (12, 14,C17). All use similar mechanisms to accomplish their catalytic activity and impressive diffusion-limited reaction rates (18,C22). However, our mechanistic analyses comparing the periplasmic SOD from with the cytoplasmic eukaryotic SODs suggested that some practical properties of bacterial (historically termed prokaryotic or P-class) and eukaryotic (E-class) SODs (19) BCR-ABL-IN-1 developed individually. Notably, periplasmic SODs are among several defenses used by pathogenic bacteria to protect themselves from your respiratory burst of their host’s innate immune response and thus to support bacterial survival and replication within phagocytes (23,C25). and are two major pathogens that continue to threaten general public health and welfare. The opportunistic bacterium colonizes the nasopharyngeal mucosa; its access to the blood can cause life-threatening infections. is definitely a leading cause of meningitis and septicemia, with BCR-ABL-IN-1 an estimated 1.2 million cases of human being meningococcal illness reported annually (26) but with nonuniform global distribution rates (27), serogroup prevalences (28), and BCR-ABL-IN-1 affected populations (29). Another Gram-negative varieties, species generating the zoonotic disease brucellosis, characterized by abortion, predominantly in ruminant animals, including cattle, bison, sheep, and goats. Furthermore, although human being brucellosis is definitely well controlled in the United States (100 instances reported yearly), more than half a million fresh instances are diagnosed globally each year (30). Illness is mostly due to laboratory contact, animal handling, or usage of tainted meat or dairy products; human being manifestations of brucellosis range from flu-like BCR-ABL-IN-1 symptoms to arthritis, epididymal/testicular swelling, endocarditis, hepatitis, and/or meningitis (31). Brucellosis consequently remains a worldwide danger.