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Rostov-na-Donu, Russia

Pisanov R.V.,Research Institute for Plague Control | Monakhova E.V.,Research Institute for Plague Control | Shalu O.A.,Research Institute for Plague Control
Russian Journal of Genetics

Sequencing of the cef (CHO cell elongating factor) gene of Vibrio cholerae serogroup O139 revealed one nucleotide substitution (T to C at nucleotide 2015) as compared to cef of classical V. cholerae O1 and two substitutions (GT to AC at nucleotides 2014-2015) as compared to cef of V. cholerae O1 El Tor. A comparative bioinformatic analysis showed that the substitution determines a threonine residue in position 672 of the Cef protein, while this position is occupied by an isoleucine residue in the classical strains and a valine residue in the El Tor strains. The latter two amino acids are hydrophobic, while threonine is hydrophilic, having a polar R group. The nonsynonymous substitution affects the predicted secondary and, probably, tertiary structures of the Cef-O139 protein and explained our previous finding that the protein fails to degrade tributyrin, while retaining the tweenase activity spectrum and all other characteristics. It cannot be excluded that the inability of Cef-O139 to cleave triglycerides, along with other genetic specifics, contribute to the fact that the O139 serogroup has been supplanted from a dominating position in etiology of cholera by the El Tor biotype. The nucleotide sequence of the V. cholerae O139 cef gene and the deduced amino acid sequence of its product are reported for the first time and were deposited in GenBank under accession nos. JF499787 and AEC04822. 1, respectively. © 2012 Pleiades Publishing, Ltd. Source

Monakhova E.V.,Research Institute for Plague Control | Pisanov R.V.,Research Institute for Plague Control | Mazrukho A.B.,Research Institute for Plague Control | Markina O.V.,Research Institute for Plague Control | Alekseeva L.P.,Research Institute for Plague Control
Molecular Genetics, Microbiology and Virology

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 bio- chemical and biological activities in vitro and in vivo were characterized. Biological activity against the cul- tured 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. © Allerton Press, Inc., 2012. Source

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