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Updated: Aug 17, 2026

Assessment of Immunologically Relevant Dynamic Tertiary Structural Features of the HIV-1 V3 Loop Crown R2 Sequence by ab initio Folding
Published on: September 15, 2010
Structural flexibility and functional valence of CD4-IgG2 (PRO 542): potential for cross-linking human
1Department of Biological Science and Structural Biology Program, Florida State University, Tallahassee, Florida 32306, USA.
Abstract:
CD4-immunoglobulin G2 (CD4-IgG2) incorporates four copies of the D1D2 domains of CD4 into an antibody-like molecule that potently neutralizes primary human immunodeficiency virus type 1. Here electron microscopy was used to explore the structure and functional valence of CD4-IgG2 in complex with gp120. CD4-gamma2, a divalent CD4-immunoglobulin fusion protein, was evaluated in parallel. Whereas CD4-gamma2-gp120 complexes adopted a simple Y-shaped structure, CD4-IgG2-gp120 complexes consisted of four gp120s arrayed about a central CD4-IgG2 molecule, a structure more reminiscent of complement C1q. Molecular modeling corroborated the electron microscopy data and further indicated that CD4-IgG2 but not CD4-gamma2 has significant potential to cross-link gp120-gp41 trimers on the virion surface, suggesting a mechanism for the heightened antiviral activity of CD4-IgG2.
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