scholarly journals Inhibition of HIV-1 Envelope Glycoprotein-mediated Cell Fusion by a DL-Amino Acid-containing Fusion Peptide

2004 ◽  
Vol 279 (46) ◽  
pp. 48224-48230 ◽  
Author(s):  
Doron Gerber ◽  
Moshe Pritsker ◽  
Susanne Gunther-Ausborn ◽  
Benitra Johnson ◽  
Robert Blumenthal ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cell Fusion ◽  
Envelope Glycoprotein ◽  
Fusion Peptide ◽  
Hiv 1

scholarly journals Role of the Membrane-Spanning Domain of Human Immunodeficiency Virus Type 1 Envelope Glycoprotein in Cell-Cell Fusion and Virus Infection

2008 ◽  
Vol 82 (11) ◽  
pp. 5417-5428 ◽  
Author(s):  
Liang Shang ◽  
Ling Yue ◽  
Eric Hunter
Keyword(s):  
Amino Acid ◽  
Cell Fusion ◽  
Viral Entry ◽  
Envelope Glycoprotein ◽  
Amino Acid Residues ◽  
Immunodeficiency Virus ◽  
Membrane Spanning ◽  
Hiv 1

ABSTRACT The membrane-spanning domain (MSD) of the human immunodeficiency virus type 1 (HIV-1) gp41 glycoprotein is critical for its biological activity. Previous C-terminal truncation studies have predicted an almost invariant core structure of 12 amino acid residues flanked by basic amino acids in the HIV-1 MSD that function to anchor the glycoprotein in the lipid bilayer. To further understand the role of specific amino acids within the MSD core, we initially replaced the core region with 12 leucine residues and then constructed recovery-of-function mutants in which specific amino acid residues (including a GGXXG motif) were reintroduced. We show here that conservation of the MSD core sequence is not required for normal expression, processing, intracellular transport, and incorporation into virions of the envelope glycoprotein (Env). However, the amino acid composition of the MSD core does influence the ability of Env to mediate cell-cell fusion and plays a critical role in the infectivity of HIV-1. Replacement of conserved amino acid residues with leucine blocked virus-to-cell fusion and subsequent viral entry into target cells. This restriction could not be released by C-terminal truncation of the gp41 glycoprotein. These studies imply that the highly conserved core residues of the HIV Env MSD, in addition to serving as a membrane anchor, play an important role in mediating membrane fusion during viral entry.

Role of Glycosphingolipids in HIV-1 Entry: Requirement of Globotriosylceramide (Gb3) in CD4/CXCR4-dependent Fusion

1999 ◽  
Vol 19 (4) ◽  
pp. 317-325 ◽  
Author(s):  
Anu Puri ◽  
Peter Hug ◽  
Kristine Jernigan ◽  
Patrick Rose ◽  
Robert Blumenthal
Keyword(s):  
Structural Analysis ◽  
Cell Fusion ◽  
Envelope Glycoprotein ◽  
Human Erythrocyte ◽  
Head Group ◽  
Specific Interactions ◽  
Cd4 Cells ◽  
Fusion Site ◽  
Hiv 1

We have recently shown that addition of human erythrocyte glycosphingolipids (GSL) to non-human CD4+ or GSL-depleted human CD4+ cells rendered those cells susceptible to gp120-gp41-mediated cell fusion (Puri et al., BBRC, 1998). One GSL fraction (Fraction 3) isolated from human erythrocyte GSL mixture exhibited the highest recovery of fusion following incorporation into CD4+ non-human and GSL-depleted HeLa-CD4 cells (HeLa-CD4/GSL-). Structural analysis of Fraction 3 showed that this GSL had identical head group as the known GSL, Gal(α1→4)Gal(β1→4)Glc-Ceramide (Gb3) (Puri et al., PNAS, 1998). Here we report that presence of Gb3 in CD4+/CXCR4+ cells but not CD4+/CXCR4- cells allows fusion with HIV-1Lai-envelope glycoprotein expressing cells (TF228). Therefore, Gb3 functions in conjunction with HIV-1 co-receptor, CXCR4 to promote fusion. We propose that Gb3 functions by recruiting CD4 and/or CXCR4 at the fusion site through structurally specific interactions.

scholarly journals Irreversible HIV-1 Inactivation Employing a Small Molecule Dual-Action Virolytic Entry Inhibitor Strategy

2019 ◽  
Author(s):  
Althea Gaffney ◽  
Aakansha Nangarlia ◽  
Steven Gossert ◽  
Adel A. Rashad ◽  
Alamgir Hossain ◽  
...  
Keyword(s):  
Amino Acid ◽  
Small Molecule ◽  
Envelope Glycoprotein ◽  
Entry Inhibitor ◽  
External Region ◽  
Design Synthesis ◽  
Dual Action ◽  
Functional Components ◽  
Amino Acid Segment ◽  
Hiv 1

The design, synthesis and validation of a family of small molecule “Dual-Action Virucidal EntryInhibitors” (DAVEIs) has been achieved that result in irreversible lytic inactivation of HIV-1 virions. These constructs contained two functional components that endow the capacity to bindsimultaneously to both the gp120 and gp41 subunits of the HIV-1 Envelope glycoprotein (Env). One component is derived from BNM-III-170, a small molecule CD4 mimic warhead that binds togp120. The second component, a Trp3 peptide, is a 9-amino acid segment based on the gp41 Membrane Proximal External Region (MPER) that has been proposed to bind to the gp41 MPERdomain of the Env. The resulting smDAVEIs both inhibit infection with low micromolar potency and induce lysis of the HIV-1 virion. The lytic activity was selective for functional HIV-1 virions. Crucially, virolysis was found to be dependent on covalent tethering of the BNM-III-170 and Trp3 domains with various spacers, as coadministration of the un-crosslinked components proved not to be lytic. Computational modeling supports a mechanism in which DAVEIs bind to open-state Env trimers and induce relative motion of gp120 subunits that further opens the trimers. Overall, this work represents a promising new step toward the use of small-molecule DAVEIs for eradication of HIV.

Molecular Cloning, Expression, and Biological Characterization of an HTLV-II Envelope Glycoprotein: HIV-1 Expression Is Permissive for HTLV-II-Induced Cell Fusion

1993 ◽  
Vol 9 (9) ◽  
pp. 849-860 ◽  
Author(s):  
BIN WANG ◽  
MICHAEL G. AGADJANYAN ◽  
VASANTHA SRIKANTAN ◽  
KENNETH E. UGEN ◽  
WILLIAM HALL ◽  
...  
Keyword(s):  
Molecular Cloning ◽  
Cell Fusion ◽  
Envelope Glycoprotein ◽  
Biological Characterization ◽  
Hiv 1

scholarly journals Capturing the inherent structural dynamics of the HIV-1 envelope glycoprotein fusion peptide

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Sonu Kumar ◽  
Anita Sarkar ◽  
Pavel Pugach ◽  
Rogier W. Sanders ◽  
John P. Moore ◽  
...  
Keyword(s):  
Structural Dynamics ◽  
Envelope Glycoprotein ◽  
Fusion Peptide ◽  
Hiv 1

scholarly journals HIV-1 Escape from a Peptidic Anchor Inhibitor through Stabilization of the Envelope Glycoprotein Spike

2016 ◽  
Vol 90 (23) ◽  
pp. 10587-10599 ◽  
Author(s):  
Dirk Eggink ◽  
Steven W. de Taeye ◽  
Ilja Bontjer ◽  
Per Johan Klasse ◽  
Johannes P. M. Langedijk ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Viral Entry ◽  
Envelope Glycoprotein ◽  
Drug Targets ◽  
Rapid Development ◽  
Fusion Peptide ◽  
Target Cells ◽  
Gp120 Subunit ◽  
Target Membrane ◽  
Hiv 1

ABSTRACTThe trimeric HIV-1 envelope glycoprotein spike (Env) mediates viral entry into cells by using a spring-loaded mechanism that allows for the controlled insertion of the Env fusion peptide into the target membrane, followed by membrane fusion. Env is the focus of vaccine research aimed at inducing protective immunity by antibodies as well as efforts to develop drugs that inhibit the viral entry process. The molecular factors contributing to Env stability and decay need to be understood better in order to optimally design vaccines and therapeutics. We generated viruses with resistance to VIR165, a peptidic inhibitor that binds the fusion peptide of the gp41 subunit and prevents its insertion into the target membrane. Interestingly, a number of escape viruses acquired substitutions in the C1 domain of the gp120 subunit (A60E, E64K, and H66R) that rendered these viruses dependent on the inhibitor. These viruses could infect target cells only when VIR165 was present after CD4 binding. Furthermore, the VIR165-dependent viruses were resistant to soluble CD4-induced Env destabilization and decay. These data suggest that VIR165-dependent Env proteins are kinetically trapped in the unliganded state and require the drug to negotiate CD4-induced conformational changes. These studies provide mechanistic insight into the action of the gp41 fusion peptide and its inhibitors and provide new ways to stabilize Env trimer vaccines.IMPORTANCEBecause of the rapid development of HIV-1 drug resistance, new drug targets need to be explored continuously. The fusion peptide of the envelope glycoprotein can be targeted by anchor inhibitors. Here we describe virus escape from the anchor inhibitor VIR165. Interestingly, some escape viruses became dependent on the inhibitor for cell entry. We show that the identified escape mutations stabilize the ground state of the envelope glycoprotein and should thus be useful in the design of stabilized envelope-based HIV vaccines.

scholarly journals Insights into the Mechanism of Inhibition of CXCR4: Identification of Piperidinylethanamine Analogs as Anti-HIV-1 Inhibitors

2015 ◽  
Vol 59 (4) ◽  
pp. 1895-1904 ◽  
Author(s):  
Debananda Das ◽  
Kenji Maeda ◽  
Yasuhiro Hayashi ◽  
Navnath Gavande ◽  
Darshan V. Desai ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Amino Acid ◽  
Envelope Glycoprotein ◽  
Site Directed Mutagenesis ◽  
Shape Similarity ◽  
Amino Acid Substitutions ◽  
Hydrogen Bond Interactions ◽  
Computational Search ◽  
Anti Hiv ◽  
Hiv 1

ABSTRACTThe cellular entry of HIV-1 into CD4+T cells requires ordered interactions of HIV-1 envelope glycoprotein with C-X-C chemokine receptor type 4 (CXCR4) receptors. However, such interactions, which should be critical for rational structure-based discovery of new CXCR4 inhibitors, remain poorly understood. Here we first determined the effects of amino acid substitutions in CXCR4 on HIV-1NL4-3glycoprotein-elicited fusion events using site-directed mutagenesis-based fusion assays and identified 11 potentially key amino acid substitutions, including D97A and E288A, which caused >30% reductions in fusion. We subsequently carried out a computational search of a screening library containing ∼604,000 compounds, in order to identify potential CXCR4 inhibitors. The computational search used the shape of IT1t, a known CXCR4 inhibitor, as a reference and employed various algorithms, including shape similarity, isomer generation, and docking against a CXCR4 crystal structure. Sixteen small molecules were identified for biological assays based on their high shape similarity to IT1t, and their putative binding modes formed hydrogen bond interactions with the amino acids identified above. Three compounds with piperidinylethanamine cores showed activity and were resynthesized. One molecule, designated CX6, was shown to significantly inhibit fusion elicited by X4 HIV-1NL4-3glycoprotein (50% inhibitory concentration [IC50], 1.9 μM), to inhibit Ca2+flux elicited by stromal cell-derived factor 1α (SDF-1α) (IC50, 92 nM), and to exert anti-HIV-1 activity (IC50, 1.5 μM). Structural modeling demonstrated that CX6 bound to CXCR4 through hydrogen bond interactions with Asp97 and Glu288. Our study suggests that targeting CXCR4 residues important for fusion elicited by HIV-1 envelope glycoprotein should be a useful and feasible approach to identifying novel CXCR4 inhibitors, and it provides important insights into the mechanism by which small-molecule CXCR4 inhibitors exert their anti-HIV-1 activities.

scholarly journals Complete functional mapping of infection- and vaccine-elicited antibodies against the fusion peptide of HIV

2018 ◽  
Author(s):  
Adam S. Dingens ◽  
Priyamvada Acharya ◽  
Hugh K. Haddox ◽  
Reda Rawi ◽  
Kai Xu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Animal Models ◽  
Fusion Peptide ◽  
Antibody Responses ◽  
Viral Escape ◽  
Single Amino Acid ◽  
Structural Basis ◽  
Major Goal ◽  
Amino Acid Mutations ◽  
Hiv 1

AbstractEliciting broadly neutralizing antibodies (bnAbs) targeting envelope (Env) is a major goal of HIV vaccine development, but cross-clade breadth from immunization has only sporadically been observed. Recently, Xu et al (2018) elicited cross-reactive neutralizing antibody responses in a variety of animal models using immunogens based on the epitope of bnAb VRC34.01. The VRC34.01 antibody, which was elicited by natural human infection, targets the N terminus of the Env fusion peptide, a critical component of the virus entry machinery. Here we precisely characterize the functional epitopes of VRC34.01 and two vaccine-elicited murine antibodies by mapping all single amino-acid mutations to the BG505 Env that affect viral neutralization. While escape from VRC34.01 occurred via mutations in both fusion peptide and distal interacting sites of the Env trimer, escape from the vaccine-elicited antibodies was mediated predominantly by mutations in the fusion peptide. Cryo-electron microscopy of four vaccine-elicited antibodies in complex with Env trimer revealed focused recognition of the fusion peptide and provided a structural basis for development of neutralization breadth. Together, these functional and structural data suggest that the breadth of vaccine-elicited antibodies targeting the fusion peptide can be enhanced by specific interactions with additional portions of Env. Thus, our complete maps of viral escape provide a template to improve the breadth or potency of future vaccine-induced antibodies against Env’s fusion peptide.Author summaryA major goal of HIV-1 vaccine design is to elicit antibodies that neutralize diverse strains of HIV-1. Recently, some of us elicited such antibodies in animal models using immunogens based on the epitope of a broad antibody (VRC34.01) isolated from an infected individual. Further improving these vaccine-elicited antibody responses will require a detailed understanding of how the resulting antibodies target HIV’s envelope protein (Env). Here, we used mutational antigenic profiling to precisely map the epitope of two vaccine-elicited antibodies and the template VRC34.01 antibody. We did this by quantifying the effect of all possible amino acid mutations to Env on antibody neutralization. Although all antibodies target a similar region of Env, we found clear differences in the functional interaction of Env with the vaccine- and infection-elicited antibodies. We combined these functional data with structural analyses to identify antibody–Env interactions that could improve the breadth of vaccine-elicited antibodies, and thereby help to refine vaccination schemes to achieve broader responses.

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