Characterization of Vibrio cholerae Cef (CHO cell elongating factor): Bioinformatics analysis and experimental data

Bioinformatics analysis of the primary and secondary structure of the Vibrio cholerae Cef (CHO cell elongating factor) protein was carried out. Similarity with triacylglycerol lipases and cytotonic toxins of other bacterial species was observed. Cef was predicted to be a heat-tolerant serine lipase with a Kunitz domain and leucine zipper. These data were confirmed experimentally. The Cefs of the two biotypes of V. cholerae O1, as well as O139 and nonO1, nonO139 serogroups, were purified from the recombinant Escherichia coli strains carrying corresponding cloned genes, and their physicochemical properties and biochemical and biological activities in vitro and in vivo were characterized. Biological activity against the cultured cells was not associated with estherase activity. Evidently, Cef is a bifunctional protein contributing both to the pathogenicity of the cholera agent and to its competitive ability in different ecological niches.