Bioinformatic Analysis of the Structural Features of the H106P/N137A Mutant as a Potential Vaccine Candidate Against Clostridium perfringens.

Background: The complex and expensive processes involved in the production of current clostridial toxoid vaccines require the design of new methods. The aim of this study was to introduce single and combined nontoxic mutants of Clostridium perfringens epsilon toxin (ETX) into the vaccine production.

Methods: Antigenic properties, amino acid sequence, physicochemical characteristics, stability, and protein structure of individual and combined ETX mutants were investigated with bioinformatics software. Spatial structure prediction was done by using a homologous modeling method based on the structure of wild type ETX (1UYJ1A.pdb) and the validity of the drawn spatial model was evaluated by estimating the quality and accuracy of the spatial chemistry of the modeled mutant proteins by Ramachandran plot.

Results: The highest instability index was observed in H106P/N137A mutant. The results of the homology modeling did not show a clear structural change in any of the mutants compared to the wild ETX. The percentages of amino acids in the favored regions, allowed regions, and outlier regions were 92.81%, 5.03%, and 2.16%, respectively, which indicate the desirability of the proposed model for the three-dimensional structure of the H106P/N137A hybrid mutant.

Conclusions: Recombinant H106P/N137A mutant of ETX can be considered a suitable candidate for the production of epsilon genetic toxoid, and this requires extensive laboratory evaluations.