Js. Kroll et al., BACTERIAL [CU,ZN]-SUPEROXIDE DISMUTASE - PHYLOGENETICALLY DISTINCT FROM THE EUKARYOTIC ENZYME, AND NOT SO RARE AFTER ALL, Microbiology, 141, 1995, pp. 2271-2279
Copper- and zinc-containing superoxide dismutases ([Cu,Zn]-SODs) are g
enerally considered almost exclusively eukaryotic enzymes, protecting
the cytosol and extracellular compartments of higher organisms from da
mage by oxygen free-radicals. The recent description of a few examples
of bacterial forms of the enzyme, located in the periplasm of differe
nt Gram-negative micro-organisms, prompted a re-evaluation of this gen
eral perception. A PCR-based approach has been developed and used succ
essfully to identify bacterial genes encoding [Cu,Zn]-SOD in a wide ra
nge of important human and animal pathogens - members of the Haemophil
us, Actinobacillus and Pasteurella (HAP) group, and Neisseria meningit
idis. Comparison of [Cu,Zn]-SOD peptide sequences found in Haemophilus
ducreyi, Actinobacillus pleuropneumoniae, Actinobacillus actinomycete
mcomitans, Pasteurella multocida, and N, meningitidis with previously
described bacterial proteins and examples of eukaryotic [Cu,Zn]-SOD ha
s shown that the bacterial proteins constitute a distinct family appar
ently widely separated in evolutionary terms from the eukaryotic examp
les. The widespread occurrence of [Cu,Zn]-SOD in the periplasm of bact
erial pathogens, appropriately located to dismute exogenously derived
superoxide radical anions, suggests that this enzyme may play a role i
n the interactive biology of organisms with their hosts and so contrib
ute to their capacity to cause disease.