Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA.
Viruses. 2022 Jul 16;14(7):1556. doi: 10.3390/v14071556.
Interactions between lysyl-tRNA synthetase (LysRS) and HIV-1 Gag facilitate selective packaging of the HIV-1 reverse transcription primer, tRNA. During HIV-1 infection, LysRS is phosphorylated at S207, released from a multi-aminoacyl-tRNA synthetase complex and packaged into progeny virions. LysRS is critical for proper targeting of tRNA to the primer-binding site (PBS) by specifically binding a PBS-adjacent tRNA-like element (TLE), which promotes release of the tRNA proximal to the PBS. However, whether LysRS phosphorylation plays a role in this process remains unknown. Here, we used a combination of binding assays, RNA chemical probing, and small-angle X-ray scattering to show that both wild-type (WT) and a phosphomimetic S207D LysRS mutant bind similarly to the HIV-1 genomic RNA (gRNA) 5'UTR via direct interactions with the TLE and stem loop 1 (SL1) and have a modest preference for binding dimeric gRNA. Unlike WT, S207D LysRS bound in an open conformation and increased the dynamics of both the PBS region and SL1. A new working model is proposed wherein a dimeric phosphorylated LysRS/tRNA complex binds to a gRNA dimer to facilitate tRNA primer release and placement onto the PBS. Future anti-viral strategies that prevent this host factor-gRNA interaction are envisioned.
赖氨酸 tRNA 合成酶（LysRS）与 HIV-1 Gag 之间的相互作用有助于选择性包装 HIV-1 逆转录引物 tRNA。在 HIV-1 感染过程中，LysRS 在 S207 处被磷酸化，从多氨酰-tRNA 合成酶复合物中释放出来，并包装到新生病毒粒子中。LysRS 对于通过特异性结合 PBS 相邻 tRNA 样元件（TLE）将 tRNA 正确靶向引物结合位点（PBS）至关重要，TLE 促进 PBS 附近 tRNA 的释放。然而，LysRS 磷酸化是否在此过程中发挥作用尚不清楚。在这里，我们使用结合测定、RNA 化学探测和小角度 X 射线散射的组合表明，野生型（WT）和磷酸模拟 S207D LysRS 突变体通过与 TLE 和茎环 1（SL1）的直接相互作用类似地结合 HIV-1 基因组 RNA（gRNA）5'UTR，并且对结合二聚体 gRNA 具有适度的偏好。与 WT 不同，S207D LysRS 以开放构象结合，并增加了 PBS 区域和 SL1 的动力学。提出了一个新的工作模型，其中二聚体磷酸化 LysRS/tRNA 复合物结合到 gRNA 二聚体上，以促进 tRNA 引物的释放和放置到 PBS 上。预计未来将有防止这种宿主因子-gRNA 相互作用的抗病毒策略。
