A cell free protein fragment complementation assay for monitoring the core interaction of the human cytomegalovirus nuclear egress complex

► A new β-lactamase based cell free protein fragment complementation assay (iPCA) was established. ► The iPCA showed that the core interaction of the nuclear egress complex of HCMV relies on a linear motif. ► The new pUL50-pUL53 interaction assay allowed identification of peptide inhibitors.