Kara Hesna, Ponchon Luc, Bouaziz Serge
Sorbonne Paris Cité, Laboratoire de Cristallographie et RMN Biologiques, Université Paris Descartes, UMR 8015 CNRS, 4 Av. de l'Observatoire, Paris, France.
Biomol NMR Assign. 2018 Apr;12(1):37-42. doi: 10.1007/s12104-017-9776-1. Epub 2017 Sep 22.
The HIV-1 viral protein R (Vpr) is incorporated into virus particle during budding suggesting that its presence in the mature virion is required in the early steps of the virus life cycle in newly infected cells. Vpr is released into the host cell cytoplasm to participate to the translocation of the preintegration complex (PIC) into the nucleus for integration of the viral DNA into the host genome. Actually, Vpr plays a key role in the activation of the transcription of the HIV-1 long terminal repeat (LTR), mediates cell cycle arrest in G2 to M transition, facilitates apoptosis and controls the fidelity of reverse transcription. Moreover, Vpr drives the repair enzyme uracil DNA glycosylase (UNG2) towards degradation. UNG2 has a major role in "Base excision repair" (BER) whose main function is to maintain genome integrity by controlling DNA uracilation. The interaction of Vpr with the cellular protein UNG2 is a key event in various stages of retroviral replication and its role remains to be defined. We have performed the structural study of UNG2 by NMR and we report its (HN, CC and C') chemical shift backbone assignment and its secondary structure in solution as predicted by TALOS-N. We aim to determine with accuracy by NMR, the residues of UNG2 interacting with Vpr, characterize their interaction and use the local structure of UNG2 and its interface with Vpr to propose potential ligands disturbing this interaction.
HIV-1病毒蛋白R（Vpr）在出芽过程中被整合到病毒颗粒中，这表明其在成熟病毒体中的存在对于新感染细胞中病毒生命周期的早期步骤是必需的。Vpr被释放到宿主细胞细胞质中，参与前整合复合物（PIC）向细胞核的转运，以便将病毒DNA整合到宿主基因组中。实际上，Vpr在HIV-1长末端重复序列（LTR）转录的激活中起关键作用，介导细胞周期在G2到M期的转换，促进细胞凋亡并控制逆转录的保真度。此外，Vpr促使修复酶尿嘧啶DNA糖基化酶（UNG2）降解。UNG2在“碱基切除修复”（BER）中起主要作用，其主要功能是通过控制DNA尿嘧啶化来维持基因组完整性。Vpr与细胞蛋白UNG2的相互作用是逆转录病毒复制各个阶段的关键事件，其作用仍有待确定。我们通过核磁共振（NMR）对UNG2进行了结构研究，并报告了其（HN、CC和C'）化学位移主链归属以及TALOS-N预测的其在溶液中的二级结构。我们旨在通过核磁共振准确确定与Vpr相互作用的UNG2残基，表征它们的相互作用，并利用UNG2的局部结构及其与Vpr的界面来提出可能干扰这种相互作用的配体。
