Structural Insights into HIV-1 Vif-APOBEC3F Interaction
Structural Insights into HIV-1 Vif-APOBEC3F Interaction
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DOI：
10.1128/jvi.02369-15
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发表时间：
2016-01-01
影响因子：
5.4
通讯作者：
Iwatani, Yasumasa
中科院分区：
文献类型：
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作者：
Nakashima, Masaaki;Ode, Hirotaka;Iwatani, Yasumasa
HIV-1 Vif 蛋白通过特异性靶向蛋白酶体降解，使病毒感染细胞中的细胞抗病毒胞苷脱氨酶 APOBEC3F (A3F) 失活。几项研究鉴定了参与 A3F 相互作用的 Vif 序列基序，而 Vif 结合 A3F 界面是基于我们对高度相似的 APOBEC3C (A3C) 的分析提出的。然而，对特定 Vif-A3F 识别的结构机制仍知之甚少。在这里，我们报告了 HIV-1 Vif 和 A3F 分子相互作用界面的结构特征。 Vif 的丙氨酸扫描分析表明，位于保守 Vif F1-、F2- 和 F3-box 基序内的六个残基对于 A3C 和 A3F 降解都是必需的，另外四个残基是 A3F 降解所必需的。 HIV-1 Vif 晶体结构上的 Vif 结构建模表明，Vif F1-、F2-和 F3-box 基序的三个不连续柔性环在空间上聚集形成柔性 A3F 相互作用界面，该界面代表疏水性和带正电的表面。我们发现与 A3C 和 A3F 交互所涉及的基本 Vif 接口补丁（R17、E171 和 R173）有所不同。此外，我们的晶体结构测定和对 A3F C 端结构域的广泛突变分析表明，A3F 界面包含对 Vif 相互作用至关重要的独特酸性延伸（L291、A292、R293 和 E324），这表明与 A3C 界面相比，Vif 界面具有额外的静电互补性。总而言之，这些发现为 A3F-Vif 相互作用机制提供了结构性见解，这将为利用细胞胞苷脱氨酶开发新型抗 HIV-1 药物提供重要基础。重要性 HIV-1 Vif 靶向细胞抗病毒 APOBEC3F (A3F) 酶进行降解。然而，特异性 A3F 识别的结构机制的细节仍不清楚。本研究报告了 HIV-1 Vif 和 A3F 分子相互作用界面的结构特征。 Vif、F1、F2 和 F3 盒的三个不连续序列基序组装形成 A3F 交互界面。此外，我们还确定了负责 Vif 相互作用的野生型 A3F C 端结构域的晶体结构。这些结果表明静电和疏水相互作用是驱动 Vif-A3F 结合的关键力，并且 Vif-A3F 界面大于 Vif-A3C 界面。这些发现将使我们能够确定Vif-A3F复合物的构型并构建该复合物的结构模型，这将为抑制剂的开发提供重要基础。
The HIV-1 Vif protein inactivates the cellular antiviral cytidine deaminase APOBEC3F (A3F) in virus-infected cells by specifically targeting it for proteasomal degradation. Several studies identified Vif sequence motifs involved in A3F interaction, whereas a Vif-binding A3F interface was proposed based on our analysis of highly similar APOBEC3C (A3C). However, the structural mechanism of specific Vif-A3F recognition is still poorly understood. Here we report structural features of interaction interfaces for both HIV-1 Vif and A3F molecules. Alanine-scanning analysis of Vif revealed that six residues located within the conserved Vif F1-, F2-, and F3-box motifs are essential for both A3C and A3F degradation, and an additional four residues are uniquely required for A3F degradation. Modeling of the Vif structure on an HIV-1 Vif crystal structure revealed that three discontinuous flexible loops of Vif F1-, F2-, and F3-box motifs sterically cluster to form a flexible A3F interaction interface, which represents hydrophobic and positively charged surfaces. We found that the basic Vif interface patch (R17, E171, and R173) involved in the interactions with A3C and A3F differs. Furthermore, our crystal structure determination and extensive mutational analysis of the A3F C-terminal domain demonstrated that the A3F interface includes a unique acidic stretch (L291, A292, R293, and E324) crucial for Vif interaction, suggesting additional electrostatic complementarity to the Vif interface compared with the A3C interface. Taken together, these findings provide structural insights into the A3F-Vif interaction mechanism, which will provide an important basis for development of novel anti-HIV-1 drugs using cellular cytidine deaminases.IMPORTANCEHIV-1 Vif targets cellular antiviral APOBEC3F (A3F) enzyme for degradation. However, the details on the structural mechanism for specific A3F recognition remain unclear. This study reports structural features of interaction interfaces for both HIV-1 Vif and A3F molecules. Three discontinuous sequence motifs of Vif, F1, F2, and F3 boxes, assemble to form an A3F interaction interface. In addition, we determined a crystal structure of the wild-type A3F C-terminal domain responsible for the Vif interaction. These results demonstrated that both electrostatic and hydrophobic interactions are the key force driving Vif-A3F binding and that the Vif-A3F interfaces are larger than the Vif-A3C interfaces. These findings will allow us to determine the configurations of the Vif-A3F complex and to construct a structural model of the complex, which will provide an important basis for inhibitor development.