Design and Synthesis of a Quenched Fluorogenic Peptide Substrate for Human Cytomegalovirus Proteinase

A fluorogenic peptide substrate for HCMV proteinase was synthesized by solid-phase peptide synthesis. The amino acid sequence of this substrate is derived from the maturation cleavage site (M site) of the natural substrate, the assembly protein precursor. The minimum sequence for efficient cleavage requires at least seven residues (P4-P3′). A systematic modification of the peptide substrate was carried out to identify positions suitable for the introduction of the fluorescent donor and the quencher acceptor groups.