Article

Vibrio cholerae periplasmic superoxide dismutase: Isolation of the gene and overexpression of the protein

University of Rome Tor Vergata, Roma, Latium, Italy
Journal of Biotechnology (Impact Factor: 2.88). 05/2004; 109(1-2):123-30. DOI: 10.1016/j.jbiotec.2004.01.002
Source: PubMed

ABSTRACT Superoxide dismutases are ubiquitous enzymes which play an important role in protecting cells against oxidative damage and which have also been shown to contribute to the pathogenicity of many bacterial species. Here we demonstrate that Vibrio cholerae, the causative agent of cholerae, expresses an active periplasmic Cu,Zn superoxide dismutase. Moreover, we have set up an expression system yielding large amounts of V. cholerae recombinant Cu,Zn superoxide dismutase in the periplasm of Escherichia coli and a procedure to obtain the enzyme in a highly purified form. Unlike the bovine enzyme, V. cholerae Cu,Zn superoxide dismutase has been proved to be highly resistant to inactivation by hydrogen peroxide. This property, which appears to be common to other bacterial enzymes of this class, might improve the ability of Cu,Zn superoxide dismutase to protect bacteria against the reactive oxygen species produced by phagocytes.

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    • "Signal peptidase I (SpI) removes the leader sequence from proteins which are to be exported in the periplasmic space or secreted in the extracellular milieu, while signal peptidase II (SpII) removes the leader peptide from lipid-modified precursor of exported proteins, which are targeted to the periplasmic inner and outer membranes. The N-terminal region of most SodC proteins from Gram-negative bacteria shows the typical features of the signal peptides recognized by SpI [33], whereas the signal sequences of mycobacterial SodC proteins are recognized by SpII [27]. Analysis of the amino acids sequences of SodC-F1 and SodC-F2 through the Lipo P program showed that the leader peptide sequence of the two prophage encoded sodC genes possess features compatible with processing either by SpI or by SpII (Figure 3). "
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