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M9640653.TXT
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1996-03-04
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Document 0653
DOCN M9640653
TI The molecular target of bicyclams, potent inhibitors of human
immunodeficiency virus replication.
DT 9604
AU de Vreese K; Kofler-Mongold V; Leutgeb C; Weber V; Vermeire K; Schacht
S; Anne J; de Clercq E; Datema R; Werner G; Rega Institute for Medical
Research, Katholieke Universiteit; Leuven, Belgium.
SO J Virol. 1996 Feb;70(2):689-96. Unique Identifier : AIDSLINE
MED/96135175
AB Bicyclams are a novel class of antiviral compounds which act as potent
and selective inhibitors of the replication of human immunodeficiency
virus type 1 (HIV-1) and HIV-2. They block an early step in the viral
life cycle following adsorption to the CD4 receptor and preceding
reverse transcription. To identify the molecular target of these
compounds, we genetically analyzed variants of the HIV-1 molecular clone
NL4-3, which developed resistance against two structurally related
bicyclams, JM2763 and the more potent SID791. The resistant strains were
obtained after long-term passaging in MT-4 cells in the presence of
progressively increasing compound concentrations. Recombinants between
selected genes of the resistant strains and the parental NL4-3 provirus
were generated by adapting the marker rescue technique to MT-4 cells.
The bicyclam-resistant phenotype was rescued by transferring the
envelope gp120 gene of bicyclam-resistant virus into the NL4-3 parental
genetic background. In the gp120 genes of the resistant strains, we
identified several mutations leading to amino acid substitutions in the
V3 loop. Furthermore, two substitutions of highly conserved amino acids
in close proximity to the disulfide bridges of the V3 and V4 loops were
found in both SID791- and JM2763-resistant strains. Additional mutations
in regions encoding V3, C4, V5, and C5 were present in SID791-resistant
viruses. Recombination experiments with overlapping parts of the
envelope gene indicated that most, if not all, of the mutations were
necessary to develop the fully SID791 resistant phenotype. The mutations
in the C-terminal part of gp120 downstream of the V3 loop sequence
conferred partial resistance to JM2763 but did not significantly
decrease susceptibility to SID791. The genetic data and the biological
properties of the resistant viruses point to inhibition of entry and
fusion as the mode of action of the HIV-inhibitory bicyclams. A possible
mechanism of binding of bicyclams to gp120 leading to inhibition of
unfolding of gp120 and its shedding from the gp41 fusion domain is
discussed.
DE Amino Acid Sequence Antiviral Agents/CHEMISTRY/*PHARMACOLOGY Base
Sequence Binding Sites Cell Line Drug Resistance, Microbial/GENETICS
Genes, env Heterocyclic Compounds/CHEMISTRY/*PHARMACOLOGY Human HIV
Envelope Protein gp120/DRUG EFFECTS/GENETICS HIV-1/*DRUG
EFFECTS/ISOLATION & PURIF Molecular Sequence Data Mutation Peptide
Fragments/DRUG EFFECTS/GENETICS Structure-Activity Relationship
Support, Non-U.S. Gov't JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).