scholarly journals Peptides Corresponding to the Heptad Repeat Motifs in the Transmembrane Protein (gp41) of Human Immunodeficiency Virus Type 1 Elicit Antibodies to Receptor-Activated Conformations of the Envelope Glycoprotein

2001 ◽  
Vol 75 (18) ◽  
pp. 8859-8863 ◽  
Author(s):  
Eve de Rosny ◽  
Russell Vassell ◽  
Paul T. Wingfield ◽  
Carl T. Wild ◽  
Carol D. Weiss
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Transmembrane Protein ◽  
Heptad Repeat ◽  
Immunodeficiency Virus ◽  
Protein Gp41 ◽  
Hiv 1 ◽  
Bundle Structure

ABSTRACT Two heptad repeat regions in the ectodomain of the human immunodeficiency virus type 1 (HIV-1) transmembrane subunit (gp41) self-assemble into a six-helix bundle structure that is critical for virus entry. Immunizations with peptides corresponding to these regions generated antibodies specific to the receptor-activated conformations of gp41.

scholarly journals Structure-Function Studies of the Self-Assembly Domain of the Human Immunodeficiency Virus Type 1 Transmembrane Protein gp41

2000 ◽  
Vol 74 (11) ◽  
pp. 5368-5372 ◽  
Author(s):  
Yongkai Weng ◽  
Zhongning Yang ◽  
Carol D. Weiss
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Self Assembly ◽  
Transmembrane Protein ◽  
Helix Bundle ◽  
Immunodeficiency Virus ◽  
Protein Gp41 ◽  
Bundle Structure

ABSTRACT The coiled-coil region of the human immunodeficiency virus type 1 transmembrane protein (gp41) makes up the interior core of the six-helix bundle structure of the gp41 self-assembly domain. We extended our previous study of this domain (Y. Weng and C. D. Weiss, J. Virol. 72:9676–9682, 1998) by analyzing 23 additional mutants at positions that lie at the interface of the interior core and outer helices. We found nine new functional mutants. For most mutants, the activity could be explained by the ability of the modeled mutants to stabilize the six-helix bundle structure. The present study provides insights into the envelope glycoprotein fusion mechanism and information for rational drug and vaccine design.

scholarly journals Sensitivity of Human Immunodeficiency Virus Type 1 to the Fusion Inhibitor T-20 Is Modulated by Coreceptor Specificity Defined by the V3 Loop of gp120

2000 ◽  
Vol 74 (18) ◽  
pp. 8358-8367 ◽  
Author(s):  
Cynthia A. Derdeyn ◽  
Julie M. Decker ◽  
Jeffrey N. Sfakianos ◽  
Xiaoyun Wu ◽  
William A. O'Brien ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Transmembrane Protein ◽  
Surface Glycoprotein ◽  
Heptad Repeat ◽  
V3 Loop ◽  
Immunodeficiency Virus ◽  
The Mean

ABSTRACT T-20 is a synthetic peptide that potently inhibits replication of human immunodeficiency virus type 1 by interfering with the transition of the transmembrane protein, gp41, to a fusion active state following interactions of the surface glycoprotein, gp120, with CD4 and coreceptor molecules displayed on the target cell surface. Although T-20 is postulated to interact with an N-terminal heptad repeat within gp41 in a trans-dominant manner, we show here that sensitivity to T-20 is strongly influenced by coreceptor specificity. When 14 T-20-naive primary isolates were analyzed for sensitivity to T-20, the mean 50% inhibitory concentration (IC50) for isolates that utilize CCR5 for entry (R5 viruses) was 0.8 log10 higher than the mean IC50 for CXCR4 (X4) isolates (P = 0.0055). Using NL4.3-based envelope chimeras that contain combinations of envelope sequences derived from R5 and X4 viruses, we found that determinants of coreceptor specificity contained within the gp120 V3 loop modulate this sensitivity to T-20. The IC50 for all chimeric envelope viruses containing R5 V3 sequences was 0.6 to 0.8 log10higher than that for viruses containing X4 V3 sequences. In addition, we confirmed that the N-terminal heptad repeat of gp41 determines the baseline sensitivity to T-20 and that the IC50 for viruses containing GIV at amino acid residues 36 to 38 was 1.0 log10 lower than the IC50 for viruses containing a G-to-D substitution. The results of this study show that gp120-coreceptor interactions and the gp41 N-terminal heptad repeat independently contribute to sensitivity to T-20. These results have important implications for the therapeutic uses of T-20 as well as for unraveling the complex mechanisms of virus fusion and entry.

scholarly journals Identification of a Critical Motif for the Human Immunodeficiency Virus Type 1 (HIV-1) gp41 Core Structure: Implications for Designing Novel Anti-HIV Fusion Inhibitors

2008 ◽  
Vol 82 (13) ◽  
pp. 6349-6358 ◽  
Author(s):  
Yuxian He ◽  
Jianwei Cheng ◽  
Jingjing Li ◽  
Zhi Qi ◽  
Hong Lu ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Core Structure ◽  
Heptad Repeat ◽  
Fusion Inhibitors ◽  
Immunodeficiency Virus ◽  
Anti Hiv ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) entry into the host cell involves a cascade of events and currently represents one of most attractive targets in the search for new antiviral drugs. The fusion-active gp41 core structure is a stable six-helix bundle (6-HB) folded by its trimeric N-terminal heptad repeat (NHR) and C-terminal heptad repeat (CHR). Peptides derived from the CHR region of HIV-1 gp41 are potent fusion inhibitors that target the NHR to block viral and cellular membrane fusion in a dominant negative fashion. However, all CHR peptides reported to date are derived primarily from residues 628 to 673 of gp41; little attention has been paid to the upstream sequence of the pocket binding domain (PBD) in the CHR. Here, we have identified a motif (621QIWNNMT627) located at the upstream region of the gp41 CHR, immediately adjacent to the PBD (628WMEWEREI635). Biophysical characterization demonstrated that this motif is critical for the stabilization of the gp41 6-HB core. The peptide CP621-652, containing the 621QIWNNMT627 motif, was able to interact with T21, a counterpart peptide derived from the NHR, to form a typical 6-HB structure with a high thermostability (thermal unfolding transition [T m ] value of 82°C). In contrast, the 6-HB formed by the peptides N36 and C34, which has been considered to be a core structure of the fusion-active gp41, had a T m of 64°C. Different from T-20 (brand name Fuseon), which is the first and only HIV-1 fusion inhibitor approved for clinical use, CP621-652 could efficiently block 6-HB formation in a dose-dependent manner. Significantly, CP621-652 had potent inhibitory activity against HIV-1-mediated cell-cell fusion and infection, especially against T-20- and C34-resistant virus. Therefore, our works provide important information for understanding the core structure of the fusion-active gp41 and for designing novel anti-HIV peptides.

scholarly journals Dissection of Human Immunodeficiency Virus Type 1 Entry with Neutralizing Antibodies to gp41 Fusion Intermediates

2002 ◽  
Vol 76 (13) ◽  
pp. 6780-6790 ◽  
Author(s):  
Hana Golding ◽  
Marina Zaitseva ◽  
Eve de Rosny ◽  
Lisa R. King ◽  
Jody Manischewitz ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Heptad Repeat ◽  
Helix Bundle ◽  
Suboptimal Temperature ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) entry requires conformational changes in the transmembrane subunit (gp41) of the envelope glycoprotein (Env) involving transient fusion intermediates that contain exposed coiled-coil (prehairpin) and six-helix bundle structures. We investigated the HIV-1 entry mechanism and the potential of antibodies targeting fusion intermediates to block Env-mediated membrane fusion. Suboptimal temperature (31.5°C) was used to prolong fusion intermediates as monitored by confocal microscopy. After transfer to 37°C, these fusion intermediates progressed to syncytium formation with enhanced kinetics compared with effector-target (E/T) cell mixtures that were incubated only at 37°C. gp41 peptides DP-178, DP-107, and IQN17 blocked fusion more efficiently (5- to 10-fold-lower 50% inhibitory dose values) when added to E/T cells at the suboptimal temperature prior to transfer to 37°C. Rabbit antibodies against peptides modeling the N-heptad repeat or the six-helix bundle of gp41 blocked fusion and viral infection at 37°C only if preincubated with E/T cells at the suboptimal temperature. Similar fusion inhibition was observed with human six-helix bundle-specific monoclonal antibodies. Our data demonstrate that antibodies targeting gp41 fusion intermediates are able to bind to gp41 and arrest fusion. They also indicate that six-helix bundles can form prior to fusion and that the lag time before fusion occurs may include the time needed to accumulate preformed six-helix bundles at the fusion site.

scholarly journals Role of the Envelope Genetic Context in the Development of Enfuvirtide Resistance in Human Immunodeficiency Virus Type 1-Infected Patients

2006 ◽  
Vol 80 (17) ◽  
pp. 8807-8819 ◽  
Author(s):  
Béatrice Labrosse ◽  
Laurence Morand-Joubert ◽  
Armelle Goubard ◽  
Séverine Rochas ◽  
Jean-Louis Labernardière ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Heptad Repeat ◽  
Fusion Inhibitor ◽  
Replicative Capacity ◽  
Immunodeficiency Virus ◽  
Genetic Context ◽  
Hiv 1

ABSTRACT Acquired human immunodeficiency virus type 1(HIV-1) resistance to the fusion inhibitor enfuvirtide (ENF) is primarily associated with mutations within the highly conserved first heptad repeat (HR1) region of gp41. Viral env sequences, however, are remarkably variable, and the envelope genetic background could have an important impact on optimal expression of HR1 mutations. We have examined the genetic evolution of env sequences, ENF susceptibility, and Env replicative capacity in patients failing ENF treatment. Sequential plasma-derived virus populations, obtained from six patients initiating ENF treatment as part of a salvage therapy, were studied using a recombinant phenotypic assay evaluating the entire gp120 and the gp41 ectodomains. Regardless of major differences in the baseline ENF susceptibilities, viral populations with similar phenotypic ENF resistance (50% inhibitory concentration, >3,000 ng/ml) were selected under treatment in four of six patients. As expected, in all patients ENF-resistant viruses harbored one or more HR1 mutations (positions 36, 38, and 43). Interestingly, in five patients the emergence of resistance mutations was not associated with reduced Env replicative capacity. Phylogenetic analysis of env sequences in sequential samples from two patients showed that the HR1 mutations had emerged in the context of env quasi-species that were different from those prevalent at baseline. Thus, the envelope genetic context appears to play a critical role in the selection of HR1 mutations and the expression of ENF resistance, thereby conditioning the evolution of HIV-1 under fusion inhibitor selective pressure.

scholarly journals Identification of a gp41 Core-Binding Molecule with Homologous Sequence of Human TNNI3K-Like Protein as a Novel Human Immunodeficiency Virus Type 1 Entry Inhibitor

2010 ◽  
Vol 84 (18) ◽  
pp. 9359-9368 ◽  
Author(s):  
Yun Zhu ◽  
Lu Lu ◽  
Liling Xu ◽  
Hengwen Yang ◽  
Shibo Jiang ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Critical Role ◽  
Heptad Repeat ◽  
Helix Bundle ◽  
Immunodeficiency Virus ◽  
Anti Hiv ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) gp41 plays a critical role in the viral fusion process, and its N- and C-terminal heptad repeat domains serve as important targets for developing anti-HIV-1 drugs, like T-20 (generic name, enfuvirtide; brand name, Fuzeon). Here, we conducted a yeast two-hybrid screening on a human bone marrow cDNA library using the recombinant soluble gp41 ectodomain as the bait and identified a novel gp41 core-binding molecule, designated P20. P20 showed no homology with a current HIV fusion inhibitor, T-20, but had sequence homology to a human protein, troponin I type 3 interacting kinase (TNNI3K)-like protein. While it could bind to the six-helix bundle core structure formed by the N- and C-terminal heptad repeats, P20 did not interrupt the formation of the six-helix bundle. P20 was effective in blocking HIV-1 Env-mediated syncytium formation and inhibiting infection by a broad spectrum of HIV-1 strains with distinct subtypes and coreceptor tropism, while it was ineffective against other enveloped viruses, such as vesicular stomatitis virus and influenza A virus. P20 exhibited no significant cytotoxicity to the CD4+ cells that were used for testing antiviral activity. Among the 11 P20 mutants, four analogous peptides with a common motif (WGRLEGRRT) exhibited significantly reduced anti-HIV-1 activity, suggesting that this region is the critical active site of P20. Therefore, this peptide can be used as a lead for developing novel HIV fusion inhibitors and as a probe for studying the membrane-fusogenic mechanism of HIV.

scholarly journals Determinants of Human Immunodeficiency Virus Type 1 Resistance to gp41-Derived Inhibitory Peptides

1998 ◽  
Vol 72 (2) ◽  
pp. 986-993 ◽  
Author(s):  
Laurence T. Rimsky ◽  
Diane C. Shugars ◽  
Thomas J. Matthews
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Mechanism Of Action ◽  
Synthetic Peptide ◽  
Heptad Repeat ◽  
Amino Terminal ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT A synthetic peptide, DP178, containing amino acids 127 to 162 of the human immunodeficiency virus type 1 (HIV-1) gp41 Env glycoprotein, is a potent inhibitor of virus infection and virus mediated cell-to-cell fusion (C. Wild, T. Greenwell, and T. Matthews, AIDS Res. Hum. Retroviruses 9:1051–1053, 1993). In an effort to understand the mechanism of action of this peptide, we derived resistant variants of HIV-1IIIB and NL4-3 by serial virus passage in the presence of increasing doses of the peptide. Sequence analysis of the resistant isolates suggested that a contiguous 3-amino-acid sequence within the amino-terminal heptad repeat motif of gp41 was associated with resistance. Site-directed mutagenesis studies confirmed this observation and indicated that changes in two of these three residues were necessary for development of the resistant phenotype. Direct binding of DP178 to recombinant protein and synthetic peptide analogs containing the wild-type and mutant heptad repeat sequences revealed a strong correlation between DP178 binding and the biological sensitivity of the corresponding virus isolates to DP178. The results are discussed from the standpoints of the mechanism of action of DP178 and recent crystallographic information for a core structure of the gp41 ectodomain.

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