In silico mutagenesis: decreasing the immunogenicity of botulinum toxin type A

Abstract

Botulinum toxin serotype A is a prominent therapeutic enzyme, for both clinical and cosmetic uses. Since this protein is produced by bacteria, it exhibits an allergenic effect when subjected to human therapy. Protein mutagenesis is one method to improve the characteristics of protein. However, in silico study is needed to give suggestion of which amino acid should be mutated. Hence, a lot of money and time can be saved. This study initially screened which residue of the Botulinum toxin serotype A is B-cell epitopes both linearly and conformationally. By overlapping the B-cell epitopes with the excluded conserve sequence, seven residues were allowed to be mutated. There were two proposed muteins showing a reduction in the antigenicity probability: ΔE147, E510F, T1062F, ΔE1080, N1089M and ΔQ1090; and ΔE147, E510F, T1062F, E1080W, N1089M and ΔQ1090. Molecular dynamics simulation of the 3D proposed muteins indicated an increase of flexibility in both muteins compared to that in the native protein. Both muteins have lower antigenicity. In addition, they are similar in structure, stability and functionality compared to the native protein.

Keywords:

• Bioinformatics
• botulinum toxin type A
• B-cell epitopes prediction
• immunogenicity
• in silico mutagenesis

Acknowledgements

We thank Helen Hendaria Kamandhari, Ph.D., for her proofreading and comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We would like to thank the Faculty of Biotechnology of Universitas Surabaya for the funding.

Notes on contributors

Stanley Evander Emeltan Tjoa

Both SEET and YMV wrote the manuscript. Regarding the work collaboration, SEET conducted the mutagenesis, the 3D modelling and the stability analysis; YMV determined which consensus sequence to be mutated, the occurrence of the mutation (mutagenesis) and the analysis of the immunogenicity of the muteins; and SEDP supervised the work.

Yoanes Maria Vianney

Both SEET and YMV wrote the manuscript. Regarding the work collaboration, SEET conducted the mutagenesis, the 3D modelling and the stability analysis; YMV determined which consensus sequence to be mutated, the occurrence of the mutation (mutagenesis) and the analysis of the immunogenicity of the muteins; and SEDP supervised the work.

Sulistyo Emantoko Dwi Putra

Both SEET and YMV wrote the manuscript. Regarding the work collaboration, SEET conducted the mutagenesis, the 3D modelling and the stability analysis; YMV determined which consensus sequence to be mutated, the occurrence of the mutation (mutagenesis) and the analysis of the immunogenicity of the muteins; and SEDP supervised the work.