Interactions of substrates and inhibitors with a family of tethered HIV-1 and HIV-2 homo- and heterodimeric proteinases
| Autor: | N D Cook, J S Mills, L A Tomchak, M C Graves, J T Griffiths, John Kay, B M Dunn |
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| Rok vydání: | 1994 |
| Předmět: |
Hybrid gene
chemistry.chemical_classification biology Dimer Human immunodeficiency virus (HIV) virus diseases Active site Substrate (chemistry) Cell Biology medicine.disease_cause Biochemistry chemistry.chemical_compound Enzyme chemistry medicine biology.protein Enzyme kinetics Molecular Biology Gene |
| Zdroj: | Journal of Biological Chemistry. 269:4787-4793 |
| ISSN: | 0021-9258 |
| DOI: | 10.1016/s0021-9258(17)37613-5 |
| Popis: | Genes were constructed to encode single-chain tethered human immunodeficiency virus HIV-1/HIV-1 and HIV-2/HIV-2 homodimeric proteinases and two HIV-1/HIV-2 heterodimers which differed in the nature of the interface strands. All four constructs under the control of a heat-inducible promoter were expressed in E. coli and the resultant proteinases were purified therefrom. Kinetic parameters (Km, kcat and kcat/Km) were derived for the interaction of the tethered homo and heterodimeric proteinases with two distinct substrates at a variety of pH values. All four enzymes were comparably active toward one substrate. With the second substrate at pH 4.7, the kcat/Km value was best for the HIV-1/1 tethered homodimer, 15-fold lower for the two heterodimeric proteinases, and was reduced by an additional 6-fold for the HIV-2/2 homodimer. From the Ki values determined for the interactions of the four tethered dimer proteinases with a systematic series of synthetic inhibitors, a parallel trend was observed. Whereas several inhibitors were equipotent against all four enzymes, two were discriminatory in that they inhibited strongly the HIV-1/1 homodimer and the two heterodimeric proteinases but had little effect on the HIV -2/2 tethered homodimer (or its untethered wild-type counterpart from HIV-2). The significance of these findings for active site interaction with HIV-proteinases is considered. |
| Databáze: | OpenAIRE |
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