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Suárez-Barrera MO, Herrera-Pineda DF, Rondón-Villarreal P, Pinzón-Reyes EH, Ochoa R, Visser L, Rueda-Forero NJ. Toxic Determination of Cry11 Mutated Proteins Obtained Using Rational Design and Its Computational Analysis. Int J Mol Sci 2023; 24:ijms24109079. [PMID: 37240424 DOI: 10.3390/ijms24109079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/08/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
Cry11 proteins are toxic to Aedes aegypti, the vector of dengue, chikungunya, and Zika viruses. Cry11Aa and Cry11Bb are protoxins, which when activated present their active-toxin form in two fragments between 30 and 35 kDa respectively. Previous studies conducted with Cry11Aa and Cry11Bb genes using DNA shuffling generated variant 8, which presented a deletion in the first 73 amino acids and one at position 572 and 9 substitutions including L553F and L556W. In this study, variant 8 mutants were constructed using site-directed mutagenesis, resulting in conversion of phenylalanine (F) and tryptophan (W) to leucine (L) at positions 553 and 556, respectively, producing the mutants 8F553L, 8W556L, and 8F553L/8W556L. Additionally, two mutants, A92D and C157R, derived from Cry11Bb were also generated. The proteins were expressed in the non-crystal strain BMB171 of Bacillus thuringiensis and subjected to median-lethal concentration (LC50) tests on first-instar larvae of A. aegypti. LC50 analysis showed that the 8F553L, 8W556L, 8F553L/8W556L, and C157R variants lost their toxic activity (>500 ng·mL-1), whereas the A92D protein presented a loss of toxicity of 11.4 times that of Cry11Bb. Cytotoxicity assays performed using variant 8, 8W556L and the controls Cry11Aa, Cry11Bb, and Cry-negative BMB171 on the colorectal cancer cell line SW480 reported 30-50% of cellular viability except for BMB171. Molecular dynamic simulations performed to identify whether the mutations at positions 553 and 556 were related to the stability and rigidity of the functional tertiary structure (domain III) of the Cry11Aa protein and variant 8 showed the importance of these mutations in specific regions for the toxic activity of Cry11 against A. aegypti. This generates pertinent knowledge for the design of Cry11 proteins and their biotechnological applications in vector-borne disease control and cancer cell lines.
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Affiliation(s)
- Miguel O Suárez-Barrera
- Facultad de Ciencias Médicas y de la Salud, Instituto de Investigación Masira, Universidad de Santander, Bucaramanga 680003, Colombia
- Max Planck Tandem Group in Nanobioengineering, Institute of Chemistry, Faculty of Natural and Exacts Sciences, University of Antioquia, Medellin 050010, Colombia
| | - Diego F Herrera-Pineda
- Facultad de Ciencias Médicas y de la Salud, Instituto de Investigación Masira, Universidad de Santander, Bucaramanga 680003, Colombia
| | - Paola Rondón-Villarreal
- Facultad de Ciencias Médicas y de la Salud, Instituto de Investigación Masira, Universidad de Santander, Bucaramanga 680003, Colombia
| | - Efraín Hernando Pinzón-Reyes
- Facultad de Ciencias Médicas y de la Salud, Instituto de Investigación Masira, Universidad de Santander, Bucaramanga 680003, Colombia
- Centro de Bioinformática, Simulación y Modelado (CBSM), School of Bioinformatic, Universidad de Talca, Talca 3465548, Chile
| | - Rodrigo Ochoa
- Biophysics of Tropical Diseases, Max Planck Tandem Group, University of Antioquia, Medellin 050010, Colombia
| | - Lydia Visser
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, 9701 Groningen, The Netherlands
| | - Nohora Juliana Rueda-Forero
- Facultad de Ciencias Médicas y de la Salud, Instituto de Investigación Masira, Universidad de Santander, Bucaramanga 680003, Colombia
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Genetic Modification Approaches for Parasporins Bacillus thuringiensis Proteins with Anticancer Activity. Molecules 2021; 26:molecules26247476. [PMID: 34946558 PMCID: PMC8706377 DOI: 10.3390/molecules26247476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 12/02/2021] [Accepted: 12/06/2021] [Indexed: 11/24/2022] Open
Abstract
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.
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Pinzón-Reyes EH, Sierra-Bueno DA, Suarez-Barrera MO, Rueda-Forero NJ, Abaunza-Villamizar S, Rondón-Villareal P. Generation of Cry11 Variants of Bacillus thuringiensis by Heuristic Computational Modeling. Evol Bioinform Online 2020; 16:1176934320924681. [PMID: 32782424 PMCID: PMC7385851 DOI: 10.1177/1176934320924681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 04/07/2020] [Indexed: 12/19/2022] Open
Abstract
Directed evolution methods mimic in vitro Darwinian evolution, inducing random mutations and selective pressure in genes to obtain proteins with enhanced characteristics. These techniques are developed using trial-and-error testing at an experimental level with a high degree of uncertainty. Therefore, in silico modeling of directed evolution is required to support experimental assays. Several in silico approaches have reproduced directed evolution, using statistical, thermodynamic, and kinetic models in an attempt to recreate experimental conditions. Likewise, optimization techniques using heuristic models have been used to understand and find the best scenarios of directed evolution. Our study uses an in silico model named HeurIstics DirecteD EvolutioN, which is based on a genetic algorithm designed to generate chimeric libraries from 2 parental genes, cry11Aa and cry11Ba, of Bacillus thuringiensis. These genes encode crystal-shaped δ-endotoxins with 3 conserved domains. Cry11 toxins are of biotechnological interest because they have shown to be effective as biopesticides for disease-spreading vectors. With our heuristic model, we considered experimental parameters such as DNA fragmentation length, number of generations or simulation cycles, and mutation rate, to get characteristics of Cry11 chimeric libraries such as percentage of population identity, truncation of variants obtained from the presence of internal stop codons, percentage of thermodynamic diversity, and stability of variants. Our study allowed us to focus on experimental conditions that may be useful for the design of in vitro and in silico experiments of directed evolution with Cry toxins of 3 conserved domains. Furthermore, we obtained in silico libraries of Cry11 variants, in which structural characteristics of wild Cry families were observed in a review of a sample of in silico sequences. We consider that future studies could use our in silico libraries and heuristic computational models, as the one suggested here, to support in vitro experiments of directed evolution.
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Affiliation(s)
- Efraín Hernando Pinzón-Reyes
- Universidad de Santander, Faculty of Health Sciences, Laboratory of Molecular Biology and Biotechnology, Bucaramanga, Colombia.,Centro de Bioinformática Simulación y Modelado (CBSM), School of Bioinformatic, Universidad de Talca, Talca, Chile
| | | | - Miguel Orlando Suarez-Barrera
- Universidad de Santander, Faculty of Health Sciences, Laboratory of Molecular Biology and Biotechnology, Bucaramanga, Colombia
| | - Nohora Juliana Rueda-Forero
- Universidad de Santander, Faculty of Health Sciences, Laboratory of Molecular Biology and Biotechnology, Bucaramanga, Colombia
| | - Sebastián Abaunza-Villamizar
- Universidad de Santander, Faculty of Health Sciences, Laboratory of Molecular Biology and Biotechnology, Bucaramanga, Colombia
| | - Paola Rondón-Villareal
- Universidad de Santander, Faculty of Health Sciences, Laboratory of Molecular Biology and Biotechnology, Bucaramanga, Colombia
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