Cry1A(b)16 toxin from Bacillus thuringiensis: Theoretical refinement of three-dimensional structure and prediction of peptides as molecular markers for detection of genetically modified organisms

Proteins. 2017 Jul;85(7):1248-1257. doi: 10.1002/prot.25285. Epub 2017 Apr 18.

Abstract

Transgenic maize produced by the insertion of the Cry transgene into its genome became the second most cultivated crop worldwide. Cry gene from Bacillus thuringiensis kurstaki expresses protein derivatives of crystalline endotoxins which confer insect resistance onto the maize crop. Mandatory labeling of processed food containing or made by genetically modified organisms is in force in many countries, so, it is very urgent to develop fast and practical methods for GMO identification, for example, biosensors. In the absence of an available empirical structure of Cry1A(b)16 protein, a theoretical model was effectively generated, in this work, by homology modeling and molecular dynamics simulations based on two available homologous protein structures. Molecular dynamics simulations were carried out to refine the selected model, and an analysis of its global structure was performed. The refined models of Cry1A(b)16 showed a standard fold and structural characteristics similar to those seen in Bacillus thuringiensis Cry1A(a) insecticidal toxin and Bacillus thuringiensis serovar kurstaki Cry1A(c) toxin. After in silico analysis of Cry1A(b)16, two immunoreactive candidate peptides were selected and specific polyclonal antibodies were produced resulting in antibody-peptide interaction. Biosensing devices are expected to be developed for detection of the Cry1A(b) protein as a marker of transgenic maize in food. Proteins 2017; 85:1248-1257. © 2017 Wiley Periodicals, Inc.

Keywords: Bacillus thuringiensis; Cry1A(b)16; homology modeling; molecular dynamics simulation.

MeSH terms

  • Amino Acid Motifs
  • Animals
  • Antibodies / chemistry
  • Antibodies / isolation & purification
  • Bacillus thuringiensis / chemistry
  • Bacillus thuringiensis / immunology
  • Bacillus thuringiensis Toxins
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / immunology
  • Bacterial Toxins / chemistry*
  • Bacterial Toxins / immunology
  • Binding Sites
  • Endotoxins / chemistry*
  • Endotoxins / immunology
  • Food Analysis / methods*
  • Hemolysin Proteins / chemistry*
  • Hemolysin Proteins / immunology
  • Immunization
  • Immunoassay
  • Molecular Dynamics Simulation*
  • Peptides / administration & dosage
  • Peptides / chemical synthesis
  • Peptides / immunology
  • Plants, Genetically Modified*
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Protein Isoforms / chemistry
  • Protein Isoforms / immunology
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Rats
  • Structural Homology, Protein
  • Zea mays / genetics*
  • Zea mays / immunology

Substances

  • Antibodies
  • Bacillus thuringiensis Toxins
  • Bacterial Proteins
  • Bacterial Toxins
  • Endotoxins
  • Hemolysin Proteins
  • Peptides
  • Protein Isoforms
  • insecticidal crystal protein, Bacillus Thuringiensis