Antiviral activity of fullerene C60 nanocrystals modified with derivatives of anionic antimicrobial peptide maximin H5

Many active antiviral substances come from natural sources. In this way, peptides, isolated from Asian toad Bombina maxima, called maximins, are very promising. Most of them have good antimicrobial activity; however, derivatives of anionic 20 amino acids-long maximin H5 show also promising antiviral activity. The effect can be enhanced by binding to suitable nanocarriers such as fullerenes. In the present study, six mutants of maximin H5 were designed where aspartic acid at position 11 was replaced by asparagine, histidine, tyrosine, alanine, glycine, or valine. The binding yield of each peptide to fullerene C60 nanocrystals was studied by derivatization with fluorescent reagent fluorescamine. The antiviral activity of these peptides and peptides bound to fullerene C60 nanocrystals was studied using bacteriophage λ as a model virus. All of the designed peptides had higher antiviral activity compared to maximin H5. The highest antiviral activity was observed in case of maximin variants H5N, H5V, or H5Y. Moreover, the antiviral activity was dependent on the amount of peptide bound on the surface of fullerene C60 nanocrystals, which was enhanced by trimesic acid (benzene-1,3,5-tricarboxylic acid) treated fullerene C60 nanocrystals.