Effect of substrate residues on the P2' preference of retroviral proteinases

Péter Boross, Péter Bagossi, Terry D. Copeland, Stephen Oroszlan, John M. Louis, József Tözsér

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The substrate sequence requirements for preference toward P2' Glu residue by human immunodeficiency virus type 1 (HIV-1) proteinase were studied in both the matrix protein/capsid protein (MA/CA) and CA/p2 cleavage site sequence contexts. These sequences represent typical type 1 (- aromatic*Pro-) and type 2 (-hydrophobic*hydrophobic-) cleavage site sequences, respectively. While in the type 1 sequence context, the preference for P2' Glu over Ile or Gln was found to be strongly dependent on the ionic strength and the residues being outside the P2-P2' region of the substrate, it remained preferable in the type 2 substrates when typical type 1 substrate sequence residues were substituted into the outside regions. The pH profile of the specificity constants suggested a lower pH optimum for substrates having P2' Glu in contrast to those having uncharged residues, in both sequence contexts. The very low frequency of P2' Glu in naturally occurring retroviral cleavage sites of various retroviruses including equine infectious anemia virus (EIAV) and murine leukemia virus (MuLV) suggests that such a residue may not have a general regulatory role in the retroviral life cycle. In fact, unlike HIV-1 and HIV-2, EIAV and MuLV proteinases do not favor P2' Glu in either the MA/CA or CA/p2 sequence contexts.

Original languageEnglish
Pages (from-to)921-929
Number of pages9
JournalEuropean Journal of Biochemistry
Issue number3
Publication statusPublished - Sep 15 1999



  • HIV proteinase
  • Oligopeptide substrates
  • Retropepsins
  • Retroviral proteinases
  • Substrate specificity

ASJC Scopus subject areas

  • Biochemistry

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