Functional and Highly Cross-Linkable HIV-1 Envelope Glycoproteins Enriched in a Pretriggered Conformation.

Abstract

Binding to the receptor, CD4, drives the pretriggered, "closed" (state-1) conformation of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) trimer into more "open" conformations (states 2 and 3). Broadly neutralizing antibodies, which are elicited inefficiently, mostly recognize the state-1 Env conformation, whereas the more commonly elicited poorly neutralizing antibodies recognize states 2/3. HIV-1 Env metastability has created challenges for defining the state-1 structure and developing immunogens mimicking this labile conformation. The availability of functional state-1 Envs that can be efficiently cross-linked at lysine and/or acidic amino acid residues might assist these endeavors. To that end, we modified HIV-1AD8 Env, which exhibits an intermediate level of triggerability by CD4. We introduced lysine/acidic residues at positions that exhibit such polymorphisms in natural HIV-1 strains. Env changes that were tolerated with respect to gp120-gp41 processing, subunit association, and virus entry were further combined. Two common polymorphisms, Q114E and Q567K, as well as a known variant, A582T, additively rendered pseudoviruses resistant to cold, soluble CD4, and a CD4-mimetic compound, phenotypes indicative of stabilization of the pretriggered state-1 Env conformation. Combining these changes resulted in two lysine-rich HIV-1AD8 Env variants (E.2 and AE.2) with neutralization- and cold-resistant phenotypes comparable to those of natural, less triggerable tier 2/3 HIV-1 isolates. Compared with these and the parental Envs, the E.2 and AE.2 Envs were cleaved more efficiently and exhibited stronger gp120-trimer association in detergent lysates. These highly cross-linkable Envs enriched in a pretriggered conformation should assist characterization of the structure and immunogenicity of this labile state. IMPORTANCE The development of an efficient vaccine is critical for combating HIV-1 infection worldwide. However, the instability of the pretriggered shape (state 1) of the viral envelope glycoprotein (Env) makes it difficult to raise neutralizing antibodies against HIV-1. Here, by introducing multiple changes in Env, we derived two HIV-1 Env variants that are enriched in state 1 and can be efficiently cross-linked to maintain this shape. These Env complexes are more stable in detergent, assisting their purification. Thus, our study provides a path to a better characterization of the native pretriggered Env, which should assist vaccine development.

• Authors: Hanh T Nguyen, Alessandra Qualizza, Saumya Anang, Meiqing Zhao, Shitao Zou, Rong Zhou, Qian Wang, Shijian Zhang, Ashlesha Deshpande, Haitao Ding, Ta-Jung Chiu, Amos B Smith 3rd, John C Kappes, Joseph G Sodroski
• Journal: Journal of virology (J Virol) Vol. 96 Issue 8 Pg. e0166821 (04 27 2022) ISSN: 1098-5514 [Electronic] United States
• PMID: 35343783 (Publication Type: Journal Article)

Chemical References

• AIDS Vaccines
• Antibodies, Neutralizing
• Detergents
• Glycoproteins
• HIV Antibodies
• HIV Envelope Protein gp120
• env Gene Products, Human Immunodeficiency Virus
• Lysine

Topics

• AIDS Vaccines (genetics, immunology)
• Antibodies, Neutralizing (immunology)
• Detergents
• Glycoproteins (chemistry, immunology)
• HIV Antibodies (chemistry, metabolism)
• HIV Envelope Protein gp120 (genetics)
• HIV Infections (prevention & control)
• HIV-1 (chemistry, genetics, immunology)
• Humans
• Lysine
• Protein Conformation
• env Gene Products, Human Immunodeficiency Virus (chemistry, genetics, immunology)