Document 0270
 DOCN  M9440270
 TI    Interactions of substrates and inhibitors with a family of tethered
       HIV-1 and HIV-2 homo- and heterodimeric proteinases.
 DT    9404
 AU    Griffiths JT; Tomchak LA; Mills JS; Graves MC; Cook ND; Dunn BM; Kay J;
       Department of Biochemistry, University of Wales College of; Cardiff,
       United Kingdom.
 SO    J Biol Chem. 1994 Feb 18;269(7):4787-93. Unique Identifier : AIDSLINE
       MED/94148922
 AB    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.
 DE    Amino Acid Sequence  Aspartic Proteinases/BIOSYNTHESIS/*METABOLISM
       Cloning, Molecular  Comparative Study  Escherichia coli  HIV
       Protease/BIOSYNTHESIS/*METABOLISM  HIV Protease
       Inhibitors/METABOLISM/*PHARMACOLOGY  HIV-1/*ENZYMOLOGY
       HIV-2/*ENZYMOLOGY  Kinetics  Macromolecular Systems  Molecular Sequence
       Data  Plasmids  Polymerase Chain Reaction  Protein Hybridization
       Recombinant Proteins/BIOSYNTHESIS/METABOLISM  Structure-Activity
       Relationship  Substrate Specificity  Support, Non-U.S. Gov't  Support,
       U.S. Gov't, P.H.S.  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).