Examinando por Autor "Suarez-Barrera, Miguel Orlando"

Mostrando 1 - 4 de 4
  • Publicación
    Acceso abierto
    Computational study, synthesis and evaluation of active peptides derived from Parasporin-2 and spike protein from Alphacoronavirus against colorectal cancer cells
    (Bioscience Reports, 2021-12-08) Cruz-Laiton, Jenniffer; Suarez-Barrera, Miguel Orlando; Rondon-Villarreal, Paola; Olarte-Diaz, Andres; Guzman, Fanny; Visser, Lydia; Rueda-Forero, Nohora Juliana; Masira
    Parasporin-2Aa1 (PS2Aa1) is a toxic protein of 37 KDa (30 kDa, activated form produced by proteolysis) that was shown to be cytotoxic against specific human cancer cells, although its mechanism of action has not been elucidated yet. In order to study the role of some native peptide fragments of proteins on anticancer activity, here we investigated the cytotoxic effect of peptide fragments from domain-1 of PS2Aa1 and one of the loops present in the binding region of the virus spike protein from Alphacoronavirus (HCoV-229E), the latter according to scientific reports, who showed interaction with the human APN (h-APN) receptor, evidence corroborated through computational simulations, and thus being possible active against colon cancer cells. Peptides namely P264-G274, Loop1-PS2Aa, and Loop2-PS2Aa were synthesized using the Fmoc solid-phase synthesis and characterized by mass spectrometry (MS). Additionally, one region from loop 1 of HCoV-229E, Loop1-HCoV-229E, was also synthesized and characterized. The A4W-GGN5 anticancer peptide and 5-fluorouracil (5-FU) were taken as a control in all experiments. Circular dichroism revealed an α-helix structure for the peptides derived from PS2Aa1 (P264-G274, Loop1-PS2Aa, and Loop2-PS2Aa) and β-laminar structure for the peptide derived from Alphacoronavirus spike protein Loop1-HCoV-229E. Peptides showed a hemolysis percentage of less than 20% at 100 μM concentration. Besides, peptides exhibited stronger anticancer activity against SW480 and SW620 cells after exposure for 48 h. Likewise, these compounds showed significantly lower toxicity against normal cells CHO-K1. The results suggest that native peptide fragments from Ps2Aa1 may be optimized as a novel potential cancer-therapeutic agents.
  • Publicación
    Restringido
    Evaluación del Efecto Inhibitorio de la Comunicación Celular de Pectobacterium Carotovorum Generado por el Aislado Stenotrophomonas Sp-HSL25
    (2021-01-18) Escalante-Valek, Mariana; Rueda Forero, Nohora Juliana; Suarez-Barrera, Miguel Orlando
    Las acíl homoserina acilasas son enzimas que integran la superfamilia de las nucleófilo N-terminal (Ntn) hidrolasas, que intervienen en la degradación de señales inductoras tipo acíl homoserina lactona (AHL), su actividad permite detener la comunicación celular (QS). A través de un proyecto de bioprospección realizado en el año 2009 por el grupo de investigación BioMol, se obtuvo el aislado HSL25, identificado como Stenotrophomonas sp por medio de PCR y secuenciación molecular, donde se encontró el gen que codifica a una proteína tipo acilasa atípica, perteneciente a la familia penicilin acilasa; por esta razón, se planteó como objetivo principal evaluar la actividad inhibitoria de Quórum Sensing de la acilasa HSL-25 frente a Pectobacterium carotovorum en modelos de Solanum tuberosum. Anteriormente, Stenotrophomonas sp - HSL25 demostró aprovechar como fuente nutricional diferentes señales AHL, por ello, se efectuaron ensayos para determinar su actividad acilasa utilizando la cepa biosensor Chromobacterium violaceum (CV026) frente a las señales N-butiril-L- homoserina lactona (C4 -AHL), N-hexanoil-L-homoserina lactona (C6- HSL), N-3-oxohexanoil-L-homoserina lactona (3-oxo-C8-HSL), la N- octanoil-L-homoserina lactona (C8-HSL) y N- dodecil homoserina lactona (C12- AHL) sintéticas; adicionalmente y con el fin de asegurar que la actividad se debe únicamente a la acción de la proteína HSL25, se construyó una cepa recombinante que portara el gen descrito para la acilasa. Las cepas nativa y recombinante mostraron alta actividad en la utilización de las señales con cadena acíl lateral corta (C4 Y C6 AHL), a su vez, la suspensión extracelular de HSL25 produjo un efecto completamente inhibitorio sobre la infección causada por Pectobacterium caratovorum que origina la podredumbre blanda de la papa.
  • Publicación
    Acceso abierto
    Generation of Cry11 Variants of Bacillus thuringiensis by Heuristic Computational Modeling
    (2020-07-27) Pinzón-Reyes, Efraín Hernando; Sierra-Bueno, Daniel Alfonso; Suarez-Barrera, Miguel Orlando; Rueda-Forero, Nohora Juliana; Biomol
    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.
  • 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.