The glycans-mediated mechanism on the interactions of gp120 with CD4 and antibody: insights from molecular dynamics simulation

Abstract

N-linked glycans such as 234 and 276 gp₁₂₀ glycans are vital components of HIV evasion from humoral immunity and important for HIV-1 neutralization of many broadly neutralizing antibodies (bNAbs). However, it is unknown the action mechanism of two glycans. To investigate the roles of the glycans on the interactions of gp120 with CD4 and antibody, molecular dynamics simulations based on gp120-CD4-8ANC195 complex with 234 and 276 gp₁₂₀ glycans, 234 gp₁₂₀ glycan, 276 gp₁₂₀ glycan and without glycan were performed. Our results reveal that 276 gp₁₂₀ glycan can enhance gp120-CD4 and gp120-antibody interactions through the formation of hydrogen-bonds of the glycan with CD4 and antibody and make the binding interface of gp120, CD4 and antibody stable. 234 gp₁₂₀ glycan primarily reinforces gp120-antibody interactions and weakly affects gp120-CD4 interactions since it mainly lies between gp120 and antibody. The cooperating of two glycans can enhance gp120-CD4 and gp120-antibody associations. Through the structural analysis, it can be seen that 234 gp₁₂₀ glycan leads to moving upward of two glycans and the variable region of heavy chain, which is favorable for the interactions of gp120 with CD4 and antibody. The information obtained in this study can provide the guidance for design vaccines and small molecule inhibitors.

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234 gp120 glycan enhances gp120-antibody association. 276 gp120 glycan enhances gp120-CD4 and gp120-antibody associations. The two glycans cooperate with significantly enhancing gp120-antibody associations.

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