The influenza virus RNA genome is transcribed and replicated in the context of the viral ribonucleoprotein (vRNP) complex by the viral RNA polymerase. The nucleoprotein (NP) is the structural component of the vRNP providing a scaffold for the viral RNA. In the vRNP as well as during transcription and replication the viral polymerase interacts with NP but it is unclear which parts of the polymerase and NP mediate these interactions. Previously the C-terminal ‘627’ domain (amino acids 538–693) of PB2 was shown to interact with NP. Here we report that a fragment encompassing amino acids 146–185 of NP is sufficient to mediate this interaction. Using NMR chemical shift perturbation assays we show that amino acid region 601 to 607 of the PB2 ‘627’ domain interacts with this fragment of NP. Substitutions of these PB2 amino acids resulted in diminished RNP activity and surface plasmon resonance assays showed that amino acids D605 was essential for the interaction with NP and V606 may also play a partial role in the interaction. Collectively these results reveal a possible interaction surface between NP and the PB2 subunit of the RNA polymerase complex.

流感病毒 RNA 基因组通过病毒 RNA 聚合酶在病毒核糖核蛋白 (vRNP) 复合物的环境中转录和复制。核蛋白 (NP) 是 vRNP 的结构成分，为病毒 RNA 提供支架。在 vRNP 以及转录和复制过程中，病毒聚合酶与 NP 相互作用，但尚不清楚聚合酶和 NP 的哪些部分介导这些相互作用。以前显示 PB2 的 C 端“627”结构域（氨基酸 538-693）与 NP 相互作用。在这里，我们报告了一个包含 NP 氨基酸 146-185 的片段足以介导这种相互作用。使用 NMR 化学位移扰动测定，我们显示 PB2 '627' 域的氨基酸区域 601 至 607 与该 NP 片段相互作用。这些 PB2 氨基酸的取代导致 RNP 活性降低，表面等离子共振测定表明氨基酸 D605 对于与 NP 的相互作用是必需的，V606 也可能在相互作用中发挥部分作用。总的来说，这些结果揭示了 NP 和 RNA 聚合酶复合物的 PB2 亚基之间可能存在的相互作用表面。