The crystal structure of HIV-1 Nef protein bound to the Fyn kinase SH3 domain suggests a role for this complex in altered T cell receptor signaling
The crystal structure of HIV-1 Nef protein bound to the Fyn kinase SH3 domain suggests a role for this complex in altered T cell receptor signaling
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DOI：
10.1016/s0969-2126(97)00286-4
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发表时间：
1997-10-15
期刊：
影响因子：
5.7
通讯作者：
Dumas, C
中科院分区：
文献类型：
--
作者：
Arold, S;Franken, P;Dumas, C
背景资料：人类免疫缺陷病毒（HIV）Nef蛋白通过与参与信号转导和宿主细胞活化的特异性细胞蛋白相互作用加速获得性免疫缺陷综合征（AIDS）的毒性进展。游离Nef和与Src同源区3（SH3）结构域结合的Nef的结构对于阐明Src激酶家族SH3结构域的亲和性和特异性是重要的，并且对于开发潜在的抗艾滋病药物和疫苗也是重要的。我们已经确定了单独的HIV-I Nef蛋白的保守核心以及与野生型p59（fyn）的SH3结构域复合的HIV-I Nef蛋白的晶体结构。蛋白酪氨酸激酶（Fyn），3.0埃分辨率。结合和未结合的Nef结构的比较显示，富含脯氨酸的基序（Pro-x-x-Pro），这是牵连在SH3结合，是部分无序的结合伴侣的情况下，该基序只有完全采用左手的聚脯氨酸II型螺旋构象后，与Fyn SH3结构域形成复合物。此外，这些结构显示Nef的精氨酸残基（Arg77）如何与Fyn SH3结构域内所谓的RT环的Asp 100相互作用，并触发氢键重排，从而使环适应Nef表面。Fyn SH 3结构域的Arg 96残基与先前描述的Fyn SH 3的异亮氨酸残基特异性地容纳在Nef的相同疏水口袋中（Arg96--> IIe）突变体，其以比野生型更高的亲和力结合Nef。三维结构支持证据表明，Nef-Fyn复合物在体内形成，并且可能通过改变T细胞受体信号传导在Nef的T细胞扰动作用中具有关键作用。结合和未结合的Nef的结构揭示了SH3结合的多价性可以通过RT环中的配体诱导的柔性来实现。这些结构表明了设计特异性阻断Nef-SH 3相互作用的抑制剂的可能靶点。
Background: Human immunodeficiency virus (HIV) Nef protein accelerates virulent progression of acquired immunodeficiency syndrome (AIDS) by its interaction with specific cellular proteins involved in signal transduction and host cell activation, Nef has been shown to bind specifically to a subset of the Src family of kinases. The structures of free Nef and Nef bound to Src homology region 3 (SH3) domain are important for the elucidation of how the affinity and specificity for the Src kinase family SH3 domains are achieved, and also for the development of potential drugs and vaccines against AIDS.Results: We have determined the crystal structures of the conserved core of HIV-I Nef protein alone and in complex with the wild-type SH3 domain of the p59(fyn) protein tyrosine kinase (Fyn), at 3.0 Angstrom resolution. Comparison of the bound and unbound Nef structures revealed that a proline-rich motif (Pro-x-x-Pro), which is implicated in SH3 binding, is partially disordered in the absence of the binding partner; this motif only fully adopts a left-handed polyproline type II helix conformation upon complex formation with the Fyn SH3 domain. In addition, the structures show how an arginine residue (Arg77) of Nef interacts with Asp 100 of the so-called RT loop within the Fyn SH3 domain, and triggers a hydrogen-bond rearrangement which allows the loop to adapt to complement the Nef surface. The Arg96 residue of the Fyn SH3 domain is specifically accommodated in the same hydrophobic pocket of Nef as the isoleucine residue of a previously described Fyn SH3 (Arg96 --> IIe) mutant that binds to Nef with higher affinity than the wild type.Conclusions: The three-dimensional structures support evidence that the Nef-Fyn complex forms in vivo and may have a crucial role in the T cell perturbating action of Nef by altering T cell receptor signaling. The structures of bound and unbound Nef reveal that the multivalency of SH3 binding may be achieved by a ligand induced flexibility in the RT loop. The structures suggest possible targets for the design of inhibitors which specifically block Nef-SH3 interactions.