Computational Modeling of the Staphylococcal Enterotoxins and Their Interaction with Natural Antitoxin Compounds

  • Int J Mol Sci. 2018 Jan 3;19(1):133. doi: 10.3390/ijms19010133.
Mahantesh Kurjogi  1 ,  Praveen Satapute  2 ,  Sudisha Jogaiah  3 ,  Mostafa Abdelrahman  4  5 ,  Jayasimha Rayalu Daddam  6 ,  Venkatesh Ramu  7 ,  Lam-Son Phan Tran  8  9
Affiliations
  • 1. Plant Healthcare and Diagnostic Center, Department of Studies in Biotechnology and Microbiology, Karnatak University, Dharwad 580003, India. [email protected].
  • 2. Plant Healthcare and Diagnostic Center, Department of Studies in Biotechnology and Microbiology, Karnatak University, Dharwad 580003, India. [email protected].
  • 3. Plant Healthcare and Diagnostic Center, Department of Studies in Biotechnology and Microbiology, Karnatak University, Dharwad 580003, India. [email protected].
  • 4. Department of Botany, Faculty of Sciences, Aswan University, Aswan 81528, Egypt. [email protected].
  • 5. Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan. [email protected].
  • 6. Department of Biotechnology, Jawaharlal Nehru Technology University, Anantapur 515002, India. [email protected].
  • 7. Department of Biochemistry, Indian Institute of Science, Bengaluru 560012, India. [email protected].
  • 8. Institute of Research and Development, Duy Tan University, 03 Quang Trung, Da Nang 550000, Vietnam. [email protected].
  • 9. Signaling Pathway Research Unit, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurmi-ku, Yokohama 230-0045, Japan. [email protected].
PMID: 29301344 DOI: 10.3390/ijms19010133
Abstract

Staphylococcus aureus is an opportunistic bacterium that produces various types of toxins, resulting in serious food poisoning. Staphylococcal enterotoxins (SEs) are heat-stable and resistant to hydrolysis by digestive Enzymes, representing a potential hazard for consumers worldwide. In the present study, we used amino-acid sequences encoding SEA and SEB-like to identify their respective template structure and build the three-dimensional (3-D) models using homology modeling method. Two natural compounds, Betulin and 28-Norolean-12-en-3-one, were selected for docking study on the basis of the criteria that they satisfied the Lipinski's Rule-of-Five. A total of 14 and 13 amino-acid residues were present in the best binding site predicted in the SEA and SEB-like, respectively, using the Computer Atlas of Surface Topology of Proteins (CASTp). Among these residues, the docking study with natural compounds Betulin and 28-Norolean-12-en-3-one revealed that GLN43 and GLY227 in the binding site of the SEA, each formed a hydrogen-bond interaction with 28-Norolean-12-en-3-one; while GLY227 residue established a hydrogen bond with Betulin. In the case of SEB-like, the docking study demonstrated that ASN87 and TYR88 residues in its binding site formed hydrogen bonds with Betulin; whereas HIS59 in the binding site formed a hydrogen-bond interaction with 28-Norolean-12-en-3-one. Our results demonstrate that the toxic effects of these two SEs can be effectively treated with antitoxins like Betulin and 28-Norolean-12-en-3-one, which could provide an effective drug therapy for this pathogen.

Keywords
28-Norolean-12-en-3-one; 3-D structure; Betulin; Staphylococcus aureus; amino-acid residues; docking; enterotoxin; food poisoning; in silico.
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