HIV-1 infection begins with fusion of viral and target cell membranes. Viral attachment and membrane fusion are mediated by viral envelope spikes upon engagement with host cellular receptors. The mature envelope spikes contain three copies each of noncovalently-associated receptor-binding subunit gp120 and fusion subunit gp41. Despite considerable progress in our understanding of the structure of HIV-1 envelope glycoprotein over the last 15 years, we still do not have an atomic picture of the full-length and fully glycosylated gp120 due to enormous technical challenges associated with crystallographic studies of this protein, which is heavily coated with carbohydrates. Such a structure is, however, critical for a full understanding of gp120 function, as well as its interactions with various ligans, in particular, broadly neutralizing antibodies (bNAbs). Determination of an atomic structure of an intact HIV-1 gp120 will mark an important milestone in structural biology of HIV-1 entry, and may also guide development of antiviral therapeutics and vaccines. We have obtained diffracting crystals of a full-length and fully glycosylated HIV-1 gp120. In this application, we propose to determine crystal structures of the intact and glycosylated HIV-1 gp120 in complex with several neutralizing antibodies. We hypothesize that high-solution crystal structures of the unaltered HIV-1 gp120 will provide novel mechanistic insights into gp120 function, antibody neutralization and immune evasion. We will pursue the following specific aims: 1) We will determine the crystal structure of an intact, fully-glycosylated HIV-1 gp120;2) We will determine the crystal structure of intact gp120 in complex with 2 domain CD4 and an anti-CD4 antibody ibalizumab;3) We will determine crystal structures of HIV-1 gp120s with distinct characteristics.
The first critical step to allow HIV-1 to enter host cells is fusion of viral and target cell membranes, mediated by the HIV-1 envelope glycoprotein. There remain critical gaps in our knowledge of structural details of the envelope protein and its structural changes during the HIV-1 entry process. The proposed studies will produce an atomic picture of the intact HIV-1 envelope glycoprotein gp120 and will facilitate development of vaccines and antiviral therapeutics.
|Fu, Qingshan; Shaik, Md Munan; Cai, Yongfei et al. (2018) Structure of the membrane proximal external region of HIV-1 envelope glycoprotein. Proc Natl Acad Sci U S A 115:E8892-E8899|
|Shaik, Md Munan; Peng, Hanqin; Lu, Jianming et al. (2018) Structural basis of coreceptor recognition by HIV-1 envelope spike. Nature :|
|Cai, Yongfei; Karaca-Griffin, Selen; Chen, Jia et al. (2017) Antigenicity-defined conformations of an extremely neutralization-resistant HIV-1 envelope spike. Proc Natl Acad Sci U S A 114:4477-4482|
|Liu, Yuhang; Pan, Junhua; Cai, Yongfei et al. (2017) Conformational States of a Soluble, Uncleaved HIV-1 Envelope Trimer. J Virol 91:|
|Chen, Bing; Chou, James J (2017) Structure of the transmembrane domain of HIV-1 envelope glycoprotein. FEBS J 284:1171-1177|
|Dev, Jyoti; Park, Donghyun; Fu, Qingshan et al. (2016) Structural basis for membrane anchoring of HIV-1 envelope spike. Science 353:172-175|
|Chen, Jia; Kovacs, James M; Peng, Hanqin et al. (2015) HIV-1 ENVELOPE. Effect of the cytoplasmic domain on antigenic characteristics of HIV-1 envelope glycoprotein. Science 349:191-5|
|Bricault, Christine A; Kovacs, James M; Nkolola, Joseph P et al. (2015) A multivalent clade C HIV-1 Env trimer cocktail elicits a higher magnitude of neutralizing antibodies than any individual component. J Virol 89:2507-19|
|Chen, Jia; Frey, Gary; Peng, Hanqin et al. (2014) Mechanism of HIV-1 neutralization by antibodies targeting a membrane-proximal region of gp41. J Virol 88:1249-58|
|Kovacs, James M; Noeldeke, Erik; Ha, Heather Jiwon et al. (2014) Stable, uncleaved HIV-1 envelope glycoprotein gp140 forms a tightly folded trimer with a native-like structure. Proc Natl Acad Sci U S A 111:18542-7|