Yeast two-hybrid assay for examining human immunodeficiency virus protease heterodimer formation with dominant-negative inhibitors and multidrug-resistant variants

Anal Biochem. 2000 Jan 15;277(2):247-53. doi: 10.1006/abio.1999.4388.


The yeast two-hybrid assay was used to study the dimerization of engineered and naturally occurring variants of human immunodeficiency virus (HIV) protease (PR) monomers. Defective monomers that were previously shown to exhibit a dominant-negative (D-N) effect in cultured mammalian cells were tested for their ability to interact in the two-hybrid assay. Similarly, monomers with dimer-interface substitutions and monomers harboring in vivo selected mutations that confer multidrug resistance (mdr) in an AIDS patient were tested for interaction in yeast. Dimer formation between wt monomers with catalytic aspartates was not detected in yeast, whereas the dimerization of PR monomers harboring the acid active site substitution D25N was readily demonstrated. The use of inactive monomers harboring the D25N substitution as a genetic background for studying additional HIV PR mutations allowed for the probing of interactions between monomers with mdr-associated mutations with those based on the HIV-1 HXB2R sequence. The HTLVIII/HIV-1 HXB2R clone has been the basis for a large number of HIV-related plasmids, primers, antibodies, and other specific reagents throughout the HIV research community. The results of our assay suggest that HXB2R-based D-N PR inhibitors associate with variant monomers based on the recently obtained nucleotide sequence from an AIDS patient with a multidrug-resistant virus. These results further encourage the use of D-N PR inhibitors as antiviral agents which may complement existing small-molecule combination therapies.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acquired Immunodeficiency Syndrome / virology*
  • Dimerization
  • Drug Resistance, Multiple / genetics*
  • Genetic Engineering
  • HIV Protease / chemistry
  • HIV Protease / genetics*
  • HIV Protease Inhibitors / pharmacology
  • HIV-1 / physiology*
  • Humans
  • Mutation
  • Saccharomyces cerevisiae
  • Structure-Activity Relationship


  • HIV Protease Inhibitors
  • HIV Protease