Histidine-rich Modification of a Scorpion-derived Peptide Improves Bioavailability and Inhibitory Activity against HSV-1

Zeng, Zhengyang; Zhang, Runhong; Hong, Wei; Cheng, Yuting; Wang, Huijuan; Lang, Yange; Ji, Zhenglin; Wu, Yingliang; Li, Wenxin; Xie, Youli; Cao, Zhijian

In this study, we screened scorpion venom peptides and identified Eval418, which inhibited the initiation of HSV-1 infection. Eval418 disrupted the initial steps of infection but hardly suppressed an established HSV-1 infection, which was speculated to be a result of its poor cellular uptake. Since introducing histidine residues can improve peptide helicity and amphiphilicity, we attempted to modify Eval418 into four histidine-rich derivative peptides to improve its cellular uptake, intracellular distribution and subsequently, its antiviral activity. The helicities and amphiphilicities of the peptides were characterized by circular dichroism (CD). Anti-HSV-1 experiments showed that the modified peptides exhibited greater inhibition of HSV-1 than did the parent peptide. Especially, the modified peptide Eval418-FH5 exerted the lowest cytotoxicity and highest anti-HSV-1 activity. The results of confocal microscopy and flow cytometry analyses also revealed that Eval418-FH5 had enhanced cellular uptake and a dispersed cellular distribution.