Importance of the Number and Position of Tryptophan–Aspartate Repeats in Designing Peptide‐Based Membrane Fusion Inhibitors

To mitigate the challenge to design broad-spectrum entry inhibitors against enveloped viruses, we have designed WD-repeat containing peptides using coronin 1 as the template. We have further compared our recent results with other WD-peptides and elucidated the importance of the number and position of WD-repeats to obtain better inhibitory efficacy. These WD-repeat containing peptides inhibit pore opening by stabilizing the hemifusion intermediate.

Abstract

Enveloped viruses utilize membrane fusion to enter the host cell and cause viral diseases. Most conventional inhibitors are target-specific and ineffective against broad-spectrum viral infections. Therefore, the current scenario demands developing inhibitors to attenuate the membrane properties instead of targeting the viral proteins. In the present work, we have designed a new WD-containing peptide (dmTG-23) by introducing a WD repeat at the center of the peptide sequence using mTG-23 peptide as a template and a 14-amino acid peptide with seven WD repeats (WD-14), and tested their efficacies against the polyethylene glycol (PEG)-induced fusion assay. Our findings show that both dmTG-23 and WD-14 prevent PEG-induced fusion of small unilamellar vesicles (SUVs) with varying cholesterol concentrations, with a higher effect for dmTG-23. Moreover, we have compared our results with our previous observations on TG-23 and mTG-23 to evaluate the importance of the number and position of WD repeats in the peptide sequence to impart the highest inhibitory activity. Our results demonstrate that three WD repeat-containing dmTG-23 shows the highest efficacy against the PEG-induced fusion of SUVs by enhancing the membrane order at the acyl chain region. This result is significantly important in designing peptide-based broad-spectrum fusion inhibitors.

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