Herpesvirus Protease Assays

  • Peter Ertl
  • Linda Russell
  • Jane Angier
Part of the Methods in Molecular Medicine™ book series (MIMM, volume 24)


Herpesviruses encode a serine protease that is essential for the maturation of viral capsids (1,2). The protease is expressed as part of a polyprotein. The catalytic domain is contained within the N-terminal third of the protein, and the remainder comprises a structural “scaffold” protein. The scaffold protein is independently expressed in excess to the polyprotein from an internal initiation codon. The protease cleaves the polyprotein at two sites: one at the c-terminus of the protease catalytic domain, the release or R-site, and the other close to the c-terminus of the scaffold protein, the maturation or M-site (Fig. 1). Cleavage of the M-site follows assembly of the viral procapsids and precedes packaging of the viral DNA. The M-site sequence is conserved among the herpesviruses and has a consensus sequence (V/L)-X-A-S, with cleavage between A-S (3). Structural studies have shown that the herpesvirus proteases have a novel structure, and their essential role in capsid maturation makes them a potential target for antiviral intervention.
Fig. 1.

Cartoon illustration of the structure of the herpesvirus protease/scaffold polyprotein showing the position of the protease catalytic domain, the scafold protein, and the release and maturation cleavage sites.


Enzyme Concentration Assay Buffer Zinc Chloride Twofold Dilution Series Primary Screen 
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© Humana Press Inc. 2000

Authors and Affiliations

  • Peter Ertl
  • Linda Russell
  • Jane Angier

There are no affiliations available

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