Examinando por Materia "Cry toxins"

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  • Publicación
    Acceso abierto
    DNA secondary structure formation by DNA shuffling of the conserved domains of the Cry protein of Bacillus thuringiensis
    (2017-12) Pinzón Reyes, Efraín-Hernando; Sierra, Daniel A.; Suárez Barrera, Miguel Orlando; Orduz, Sergio; Florez, Alvaro M.
    Background The Cry toxins, or δ-endotoxins, are a diverse group of proteins produced by Bacillus thuringiensis. While DNA secondary structures are biologically relevant, it is unknown if such structures are formed in regions encoding conserved domains of Cry toxins under shuffling conditions. We analyzed 5 holotypes that encode Cry toxins and that grouped into 4 clusters according to their phylogenetic closeness. The mean number of DNA secondary structures that formed and the mean Gibbs free energy (ΔG¯¯¯¯¯¯¯¯) were determined by an in silico analysis using different experimental DNA shuffling scenarios. In terms of spontaneity, shuffling efficiency was directly proportional to the formation of secondary structures but inversely proportional to ∆G. Results The results showed a shared thermodynamic pattern for each cluster and relationships among sequences that are phylogenetically close at the protein level. The regions of the cry11Aa, Ba and Bb genes that encode domain I showed more spontaneity and thus a greater tendency to form secondary structures (<∆G). In the region of domain III; this tendency was lower (>∆G) in the cry11Ba and Bb genes. Proteins that are phylogenetically closer to Cry11Ba and Cry11Bb, such as Cry2Aa and Cry18Aa, maintained the same thermodynamic pattern. More distant proteins, such as Cry1Aa, Cry1Ab, Cry30Aa and Cry30Ca, featured different thermodynamic patterns in their DNA. Conclusion These results suggest the presence of thermodynamic variations associated to the formation of secondary structures and an evolutionary relationship with regions that encode highly conserved domains in Cry proteins. The findings of this study may have a role in the in silico design of cry gene assembly by DNA shuffling techniques.
  • Publicación
    Acceso abierto
    Genetic modification approaches for parasporins bacillus thuringiensis proteins with anticancer activity
    (MDPI, 2021-12-10) Suarez-Barrera, Miguel Orlando; Visser, Lydia; Rondon-Villarreal, Paola; Herrera-Pineda, Diego Fernando; Alarcon-Aldana, Juan S.; Van den Berg, Anke; Orozco, Jahir; Pinzon- Reyes, Efrain-Hernando; Moreno, Ernesto; Rueda Forero, Nohora Juliana; Masira
    Bacillus thuringiensis (Bt) is a bacterium capable of producing Cry toxins, which are recognized for their bio-controlling actions against insects. However, a few Bt strains encode proteins lacking insecticidal activity but showing cytotoxic activity against different cancer cell lines and low or no cytotoxicity toward normal human cells. A subset of Cry anticancer proteins, termed parasporins (PSs), has recently arisen as a potential alternative for cancer treatment. However, the molecular receptors that allow the binding of PSs to cells and their cytotoxic mechanisms of action have not been well established. Nonetheless, their selective cytotoxic activity against different types of cancer cell lines places PSs as a promising alternative treatment modality. In this review, we provide an overview of the classification, structures, mechanisms of action, and insights obtained from genetic modification approaches for PS proteins.