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Updated: Jun 6, 2026
Conformational Evaluation of HIV-1 Trimeric Envelope Glycoproteins Using a Cell-based ELISA Assay
Published on: September 14, 2014
Synthesis and analysis of the membrane proximal external region epitopes of HIV-1
Sampat Ingale1, Johannes S Gach, Michael B Zwick
1Department of Chemistry and Cell Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Abstract:
The membrane proximal external region (MPER) of gp41 abuts the viral membrane at the base of HIV-1 envelope glycoprotein spikes. The MPER is highly conserved and is rich in Trp and other lipophilic residues. The MPER is also required for the infection of host cells by HIV-1 and is the target of the broadly neutralizing antibodies, 4E10, 2F5, and Z13e1. These neutralizing antibodies are valuable tools for understanding relevant conformations of the MPER and for studying HIV-1 neutralization, but multiple approaches used to elicit MPER binding antibodies with similar neutralization properties have failed. Here we report our efforts to mimic the MPER using linear as well as constrained peptides. Unnatural amino acids were also introduced into the core epitope of 4E10 to probe requirements of antibody binding. Peptide analogs with C-terminal Api or Aib residues designed to be helical transmembrane (TM) domain surrogates exhibit enhanced binding to the 4E10 and Z13e1 antibodies. However, we find that placement of constrained amino acids at nonbinding sites within the core epitope significantly reduce binding. These results are relevant to an understanding of native MPER structure on HIV-1, and form a basis for a chemical synthesis approach to mimic MPER stricture and to construct an MPER-based vaccine.
Insights
Researchers mimicked the HIV-1 membrane proximal external region (MPER) using peptides and unnatural amino acids. This approach enhances understanding of MPER structure and aids in developing MPER-based vaccines.
Area of Science:
- Immunology
- Virology
- Biochemistry
Background:
- The membrane proximal external region (MPER) of HIV-1 gp41 is crucial for viral entry and is a target for broadly neutralizing antibodies.
- Antibodies like 4E10, 2F5, and Z13e1 recognize the MPER, but efforts to elicit similar antibodies have been challenging.
- Understanding MPER conformation is vital for HIV-1 neutralization research and vaccine development.
Purpose of the Study:
- To mimic the HIV-1 MPER using peptide analogs and unnatural amino acids.
- To investigate the structural requirements for binding to MPER-specific antibodies.
- To lay the groundwork for a synthetic MPER-based vaccine.
Main Methods:
- Synthesis of linear and constrained peptides mimicking the MPER.
- Incorporation of unnatural amino acids into peptide epitopes.
- Assessment of peptide binding to 4E10 and Z13e1 antibodies.
Main Results:
- Peptide analogs with helical transmembrane (TM) domain surrogates showed enhanced binding to 4E10 and Z13e1 antibodies.
- Constrained amino acids at non-binding sites within the epitope reduced antibody binding.
- The study provides insights into native MPER structure and antibody recognition.
Conclusions:
- Peptide-based mimicry of the MPER is a viable strategy for studying its structure and antibody interactions.
- Specific amino acid placements are critical for effective MPER-antibody binding.
- This research supports a chemical synthesis approach for developing MPER-based HIV vaccines.
