Characterization of an anti‐varicella‐zoster virus compound that targets the portal protein encoded by ORF54

ABSTRACT An anti‐varicella‐zoster virus compound, a 5‐chlorobenzo[b]thiophen derivative (45B5), was characterized. Its 50% effective concentration against the cell‐free vaccine Oka strain and 50% cytotoxic concentration in human fibroblasts were 16.9 µM and more than 100 µM, respectively. Treatment with 45B5 decreased viral DNA synthesis and IE62 expression weakly but significantly. All 45B5‐resistant viral clones isolated were found to have at least one mutation in ORF54 that encodes the portal protein. There were no effects on interaction between the portal and scaffold proteins. Thus, 45B5 may inhibit nuclear delivery of viral DNA.