Molecular Microbiology and Structural Biochemistry, Unité Mixte de Recherche 5086 CNRS/Université de Lyon, 69367 Lyon, France.
Department of Chemistry and Applied Biosciences, Institute of Molecular Physical Sciences, Eidgenössische Technische Hochschule Zurich, 8093 Zurich, Switzerland.
Proc Natl Acad Sci U S A. 2024 Nov 12;121(46):e2407731121. doi: 10.1073/pnas.2407731121. Epub 2024 Nov 7.
SARS-CoV-2 carries a sizeable number of proteins that are accessory to replication but may be essential for virus-host interactions and modulation of the host immune response. Here, we investigated the structure and interactions of the largely unknown ORF7b, a small membranous accessory membrane protein of SARS-CoV-2. We show that structural predictions indicate a transmembrane (TM) leucine zipper for ORF7b, and experimentally confirm the predominantly α-helical secondary structure within a phospholipid membrane mimetic by solid-state NMR. We also show that ORF7b forms heterogeneous higher-order multimers. We determined ORF7b interactions with cellular TM leucine zipper proteins using both biochemical and NMR approaches, providing evidence for ORF7b interaction with the TM domains of E-cadherin, as well as phospholamban. Our results place ORF7b as a hypothetical interferer in cellular processes that utilize leucine zipper motifs in transmembrane multimerization domains.
SARS-CoV-2 携带大量辅助复制的蛋白质，但这些蛋白质可能对病毒-宿主相互作用和宿主免疫反应的调节至关重要。在这里，我们研究了 SARS-CoV-2 中大量未知的 ORF7b 的结构和相互作用，ORF7b 是一种小型膜辅助膜蛋白。我们表明，结构预测表明 ORF7b 具有跨膜（TM）亮氨酸拉链，并且通过固态 NMR 实验证实了在磷脂膜类似物中主要的α-螺旋二级结构。我们还表明，ORF7b 形成异质的高阶多聚体。我们使用生化和 NMR 方法确定了 ORF7b 与细胞 TM 亮氨酸拉链蛋白的相互作用，为 ORF7b 与 E-钙粘蛋白和磷酸化酶的 TM 结构域相互作用提供了证据。我们的结果将 ORF7b 作为一种假设的干扰物，置于利用跨膜多聚化结构域亮氨酸拉链模体的细胞过程中。
