Conformational States of a Soluble, Uncleaved HIV-1 Envelope Trimer.
Conformational States of a Soluble, Uncleaved HIV-1 Envelope Trimer.
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可溶、未切割的 HIV-1 包膜三聚体的构象状态。
DOI：
10.1128/jvi.00175-17
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发表时间：
2017
影响因子：
5.4
通讯作者：
Chen,Bing
中科院分区：
文献类型：
--
作者：
Liu,Yuhang;Pan,Junhua;Cai,Yongfei;Grigorieff,Nikolaus;Harrison,StephenC;Chen,Bing
HIV-1包膜刺突[Env;三聚体（gp 160）3裂解为（gp 120/gp 41）3]诱导膜融合，导致病毒进入。它也是中和抗体靶向的病毒成分。疫苗开发需要以适于临床研究的数量生产类似于功能性Env的重组形式。HIV-1 gp 140三聚体--（gp 160）3的未切割胞外域--来自少数选定的病毒分离株，采用具有天然Env刺突的许多抗原特性的紧凑构象。目前正在进行临床试验。我们在这里报告低分辨率（20 μ m）电子冷冻显微镜（cryoEM）结构的gp 140三聚体，它采用两个主要的构象，一个封闭的，另一个稍微开放。在该分辨率下，前者与稳定的切割三聚体（SOSIP）或具有截短胞质尾的膜结合Env三聚体（EnvΔCT）所采用的结构无法区分。后一种构象更接近于部分开放的Env三聚体，而不是由CD 4诱导的完全开放的构象。这些结果表明，一个稳定的，未切割的HIV-1 gp 140三聚体有一个紧凑的结构接近的天然Env。重要的是任何HIV疫苗的蛋白质成分（无论是启动或加强）的发展需要生产的重组形式，以模拟三聚体，功能性HIV-1包膜尖峰的数量适合于临床研究。我们对包膜结构的理解部分依赖于一种被称为SOSIP.664的切割的可溶性三聚体，该三聚体通过几种修饰（包括工程二硫化物）来稳定。这种构建体很难大量生产，即使在动物模型中，也尚未诱导出比其他基于免疫原的免疫原更好的抗体应答。被称为gp 140的包膜蛋白的未切割的胞外域也被制成可溶性形式以模拟存在于病毒体表面上的天然Env。然而，大多数HIV-1 gp 140制剂并不稳定，并且具有不均匀的构象。这里呈现的结果表明，gp 140制剂从合适的分离株可以采用紧凑的，天然的结构，支持其作为候选疫苗的使用。
The HIV-1 envelope spike [Env; trimeric (gp160)3cleaved to (gp120/gp41)3] induces membrane fusion, leading to viral entry. It is also the viral component targeted by neutralizing antibodies. Vaccine development requires production, in quantities suitable for clinical studies, of a recombinant form that resembles functional Env. HIV-1 gp140 trimers—the uncleaved ectodomains of (gp160)3—from a few selected viral isolates adopt a compact conformation with many antigenic properties of native Env spikes. One is currently being evaluated in a clinical trial. We report here low-resolution (20 Å) electron cryomicroscopy (cryoEM) structures of this gp140 trimer, which adopts two principal conformations, one closed and the other slightly open. The former is indistinguishable at this resolution from those adopted by a stabilized, cleaved trimer (SOSIP) or by a membrane-bound Env trimer with a truncated cytoplasmic tail (EnvΔCT). The latter conformation is closer to a partially open Env trimer than to the fully open conformation induced by CD4. These results show that a stable, uncleaved HIV-1 gp140 trimer has a compact structure close to that of native Env.IMPORTANCEDevelopment of any HIV vaccine with a protein component (for either priming or boosting) requires production of a recombinant form to mimic the trimeric, functional HIV-1 envelope spike in quantities suitable for clinical studies. Our understanding of the envelope structure has depended in part on a cleaved, soluble trimer, known as SOSIP.664, stabilized by several modifications, including an engineered disulfide. This construct, which is difficult to produce in large quantities, has yet to induce better antibody responses than those to other envelope-based immunogens, even in animal models. The uncleaved ectodomain of the envelope protein, called gp140, has also been made as a soluble form to mimic the native Env present on the virion surface. Most HIV-1 gp140 preparations are not stable, however, and have an inhomogeneous conformation. The results presented here show that gp140 preparations from suitable isolates can adopt a compact, native-like structure, supporting its use as a vaccine candidate.