title: Trimeric HIV-1 glycoprotein gp140 immunogens and native HIV-1 envelope glycoproteins display the same closed and open quaternary molecular architectures.
abstract: The initial step in HIV-1 infection occurs with the binding of cell surface CD4 to trimeric HIV-1 envelope glycoproteins (Env), a heterodimer of a transmembrane glycoprotein (gp41) and a surface glycoprotein (gp120). The design of soluble versions of trimeric Env that display structural and functional properties similar to those observed on intact viruses is highly desirable from the viewpoint of designing immunogens that could be effective as vaccines against HIV/AIDS. Using cryoelectron tomography combined with subvolume averaging, we have analyzed the structure of SOSIP gp140 trimers, which are cleaved, solubilized versions of the ectodomain of trimeric HIV-1 Env. We show that unliganded gp140 trimers adopt a quaternary arrangement similar to that displayed by native unliganded trimers on the surface of intact HIV-1 virions. When complexed with soluble CD4, Fab 17b, which binds to gp120 at its chemokine coreceptor binding site, or both soluble CD4 and 17b Fab, gp140 trimers display an open conformation in which there is an outward rotation and displacement of each gp120 protomer. We demonstrate that the molecular arrangements of gp120 trimers in the closed and open conformations of the soluble trimer are the same as those observed for the closed and open states, respectively, of trimeric gp120 on intact HIV-1 BaL virions, establishing that soluble gp140 trimers can be designed to mimic the quaternary structural transitions displayed by native trimeric Env.
authors.affiliation: Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Audray
authors.initials: A
authors.lastname: Harris
authors.forename: Mario J
authors.initials: MJ
authors.lastname: Borgnia
authors.forename: Dan
authors.initials: D
authors.lastname: Shi
authors.forename: Alberto
authors.initials: A
authors.lastname: Bartesaghi
authors.forename: Haifeng
authors.initials: H
authors.lastname: He
authors.forename: Robert
authors.initials: R
authors.lastname: Pejchal
authors.forename: Yun Kenneth
authors.initials: YK
authors.lastname: Kang
authors.forename: Rafael
authors.initials: R
authors.lastname: Depetris
authors.forename: Andre J
authors.initials: AJ
authors.lastname: Marozsan
authors.forename: Rogier W
authors.initials: RW
authors.lastname: Sanders
authors.forename: Per Johan
authors.initials: PJ
authors.lastname: Klasse
authors.forename: Jacqueline L S
authors.initials: JL
authors.lastname: Milne
authors.forename: Ian A
authors.initials: IA
authors.lastname: Wilson
authors.forename: William C
authors.initials: WC
authors.lastname: Olson
authors.forename: John P
authors.initials: JP
authors.lastname: Moore
authors.forename: Sriram
authors.initials: S
authors.lastname: Subramaniam
mesh_terms: D016915:AIDS Vaccines / Q000737:chemistry / Q000276:immunology; D055592:Biophysical Phenomena; D015704:CD4 Antigens / Q000737:chemistry; D020285:Cryoelectron Microscopy; D015483:HIV Antibodies / Q000737:chemistry; D015488:HIV Antigens / Q000737:chemistry / Q000276:immunology; D015699:HIV Envelope Protein gp120 / Q000737:chemistry / Q000276:immunology; D015497:HIV-1 / Q000737:chemistry* / Q000276:immunology*; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry; D008024:Ligands; D008958:Models, Molecular; D020836:Protein Structure, Quaternary; D054299:env Gene Products, Human Immunodeficiency Virus / Q000737:chemistry* / Q000276:immunology* / Q000648:ultrastructure
chemical_list: D016915:AIDS Vaccines; D015704:CD4 Antigens; D015483:HIV Antibodies; D015488:HIV Antigens; D015699:HIV Envelope Protein gp120; D007140:Immunoglobulin Fab Fragments; D008024:Ligands; D054299:env Gene Products, Human Immunodeficiency Virus; C514793:gp120 protein, Human immunodeficiency virus 1; C097729:gp140 envelope protein, Human immunodeficiency virus 1