A VP2/3-derived peptide exhibits potent antiviral activity against BK and JC polyomaviruses by targeting a novel VP1 binding site

Abstract

28In pursuit of effective therapeutics for human polyomaviruses, we identified a peptide derived from 29 the BK polyomavirus (BKV) minor structural proteins VP2/3 that is a potent inhibitor of BKV 30 infection with no observable cellular toxicity. The thirteen amino acid peptide binds to major 31 structural protein VP1 in a new location within the pore with a low nanomolar KD. Alanine scanning 32 of the peptide identified three key residues, substitution of each of which results in ~1000-fold 33 loss of affinity with a concomitant reduction in antiviral activity. NMR spectroscopy and an X-ray 34 structurally-guided model demonstrate specific binding of the peptide to the pore of the VP1 35 pentamer that constitutes the BKV capsid. Cell-based assays with the peptide demonstrate 36 nanomolar inhibition of BKV infection and suggest that the peptide likely blocks the viral entry 37 pathway between endocytosis and escape from the host cell ER. The peptide motif is highly 38 conserved among the polyomavirus clade, and homologous peptides exhibit similar binding 39 properties for JC polyomavirus and inhibit infection with similar potency to BKV in a model cell 40 line. Substitutions within VP1 or VP2/3 residues involved in VP1-peptide interaction negatively 41 impact viral infectivity, potentially indicating the peptide-binding site within the VP1 pore is relevant 42 for VP1-VP2/3 interactions. The inhibitory potential of the peptide-binding site first reported here 43 may present a novel target for development of new anti-polyomavirus therapies. In summary, we 44 present the first anti-polyomavirus inhibitor that acts via a novel mechanism of action by 45 specifically targeting the pore of VP1. 46 47 48 53 54