The SARS-CoV-2 (SCoV-2) virus is the causative agent of the ongoing COVID-19 pandemic. It contains a positive sense single-stranded RNA genome and belongs to the genus of Betacoronaviruses. The 5′- and 3′-genomic ends of the 30 kb SCoV-2 genome are potential antiviral drug targets. Major parts of these sequences are highly conserved among Betacoronaviruses and contain cis-acting RNA elements that affect RNA translation and replication. The 31 nucleotide (nt) long highly conserved stem-loop 5a (SL5a) is located within the 5′-untranslated region (5′-UTR) important for viral replication. SL5a features a U-rich asymmetric bulge and is capped with a 5′-UUUCGU-3′ hexaloop, which is also found in stem-loop 5b (SL5b). We herein report the extensive ¹H, ¹³C and ¹⁵N resonance assignment of SL5a as basis for in-depth structural studies by solution NMR spectroscopy.

SARS-CoV-2 (SCoV-2) 病毒是正在进行的 COVID-19 大流行的病原体。它包含一个正链单链 RNA 基因组，属于 β 冠状病毒属。30 kb SCoV-2 基因组的 5'- 和 3'-基因组末端是潜在的抗病毒药物靶标。这些序列的主要部分在 β 冠状病毒中高度保守，并且包含影响 RNA 翻译和复制的顺式作用 RNA 元件。31 个核苷酸 (nt) 长的高度保守的茎环 5a (SL5a) 位于对病毒复制很重要的 5'-非翻译区 (5'-UTR) 内。SL5a 具有富含 U 的不对称凸起，并被 5'-UUUCGU-3' 六环覆盖，这也在茎环 5b (SL5b) 中发现。我们在此报告了广泛的¹ H、¹³ C 和SL5a 的¹⁵ N 共振分配作为溶液核磁共振光谱深入结构研究的基础。