The 80's loop (residues 78 to 85) is important for the differential activity of retroviral proteases

• Published in: Journal of molecular biology Vol. 267; no. 3; pp. 467 - 475
• Main Authors: Stebbins, J, Towler, E M, Tennant, M G, Deckman, I C, Debouck, C
• Format: Journal Article
• Language: English
• Published: England 04.04.1997
• Subjects: AIDS/HIV; Amino Acid Sequence; Animals; Aspartic Acid Endopeptidases - chemistry; Aspartic Acid Endopeptidases - genetics; Aspartic Acid Endopeptidases - metabolism; Binding Sites; Cloning, Molecular; Conserved Sequence; Escherichia coli; Escherichia coli - genetics; Fusion Proteins, gag-pol - metabolism; Gene Products, gag - metabolism; human immunodeficiency virus 1; human immunodeficiency virus 2; Humans; Hydrolysis; Lentiviruses, Primate - enzymology; Molecular Sequence Data; Oligopeptides - chemical synthesis; Oligopeptides - metabolism; Protein Conformation; Protein Engineering; Recombinant Fusion Proteins; simian immunodeficiency virus; Substrate Specificity
• ISSN: 0022-2836
• DOI: 10.1006/jmbi.1997.0891

The abundance of structural data available for retroviral proteases affords a unique opportunity to investigate structure activity relationships. Our approach attempts to genetically engineer an HIV (human immunodeficiency virus)-1 protease that is functionally equivalent to the HIV-2 and the SIV (simian immunodeficiency virus) enzymes and conversely to engineer an HIV-2 protease that is functionally equivalent to the HIV-1 enzyme. For this purpose, the HIV-2 and SIV proteases were cloned and characterized in an Escherichia coli (E. coli) assay system along with 33 engineered HIV-1 and HIV-2 enzymes. The results of these experiments show that a relatively large S1 or S1' subsite volume, which is likely determined by the conformation of the 80's loop (residues 78 to 85), is necessary to fully accommodate the HIV-1 protease specificity site AETF*YCDG (the asterisk indicates the location scissile bond) during productive binding.