Cryo-EM Structures of HIV-1 trimer bound to CD4-mimetics M48U1 and BNM-III-170 adopt a CD4-bound open conformation [article]

Claudia Angela Jette, Christopher O Barnes, Sharon Marie Kirk, Bruno Melillo, Amos Brittain Smith, Pamela J Bjorkman
2020 bioRxiv   pre-print
Human Immunodeficiency Virus-1 (HIV-1), the causative agent of AIDS, impacts millions of people. Entry into target cells is mediated by the HIV-1 envelope (Env) glycoprotein interacting with host receptor CD4, which triggers conformational changes allowing binding to a coreceptor and subsequent membrane fusion. Small molecule or peptide CD4-mimetic drugs mimic CD4's Phe43 interaction with Env by inserting into the conserved Phe43 pocket on Env subunit gp120. Here, we present single-particle
more » ... single-particle cryo-EM structures of CD4-mimetics BNM-III-170 and M48U1 bound to a BG505 native-like Env trimer plus the CD4-induced antibody 17b at 3.7Å and 3.9Å resolution, respectively. CD4-mimetic-bound BG505 exhibits canonical CD4-induced conformational changes including trimer opening, formation of the 4-stranded gp120 bridging sheet, displacement of the V1V2 loop, and formation of a compact and elongated gp41 HR1C helical bundle. We conclude that CD4-induced structural changes on both gp120 and gp41 Env subunits are induced by binding to the gp120 Phe43 pocket.
doi:10.1101/2020.08.21.261974 fatcat:deyms3gn7vdzhhlmglyu5qg7vy