ePrints@IIScePrints@IISc Home | About | Browse | Latest Additions | Advanced Search | Contact | Help

Glycosylation of the core of the HIV-1 envelope subunit protein gp120 is not required for native trimer formation or viral infectivity

Rathore, Ujjwal and Saha, Piyali and Kesavardhana, Sannula and Kumar, Aditya Arun and Datta, Rohini and Devanarayanan, Sivasankar and Das, Raksha and Mascola, John R and Varadarajan, Raghavan (2017) Glycosylation of the core of the HIV-1 envelope subunit protein gp120 is not required for native trimer formation or viral infectivity. In: JOURNAL OF BIOLOGICAL CHEMISTRY, 292 (4). pp. 10197-10219.

[img] PDF
Jou_Bio_Che_292-4_10197_2017.pdf - Published Version
Restricted to Registered users only

Download (3MB) | Request a copy
Official URL: http://dx.doi.org/10.1074/jbc.M117.788919


The gp120 subunit of the HIV-1 envelope (Env) protein is heavily glycosylated at similar to 25 glycosylation sites, of which similar to 7-8 are located in the V1/V2 and V3 variable loops and the others in the remaining core gp120 region. Glycans partially shield Env from recognition by the host immune system and also are believed to be indispensable for proper folding of gp120 and for viral infectivity. Previous attempts to alter glycosylation sites in Env typically involved mutating the glycosylated asparagine residues to structurally similar glutamines or alanines. Here, we confirmed that such mutations at multiple glycosylation sites greatly diminish viral infectivity and result in significantly reduced binding to both neutralizing and non-neutralizing antibodies. Therefore, using an alternative approach, we combined evolutionary information with structure-guided design and yeast surface display to produce properly cleaved HIV-1 Env variants that lack all 15 core gp120 glycans, yet retain conformational integrity and multiple-cycle viral infectivity and bind to several broadly neutralizing antibodies (bNAbs), including trimer-specific antibodies and a germline-reverted version of the bNAb VRC01. Our observations demonstrate that core gp120 glycans are not essential for folding, and hence their likely primary role is enabling immune evasion. We also show that our glycan removal approach is not strain restricted. Glycan-deficient Env derivatives can be used as priming immunogens because they should engage and activate a more divergent set of germlines than fully glycosylated Env. In conclusion, these results clarify the role of core gp120 glycosylation and illustrate a general method for designing glycan-free folded protein derivatives.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USA
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited: 14 Jul 2017 10:15
Last Modified: 14 Jul 2017 10:15
URI: http://eprints.iisc.ac.in/id/eprint/57381

Actions (login required)

View Item View Item