NMR characterization and ligand binding site of the stem–loop 2 motif from the Delta variant of SARS-CoV-2

Aromatic C6H6/C8H8 and ribose C1′H1′ assignment via 4D-HMQC-NOESY-HMQC. (A) ¹H, ¹³C HSQC of the aromatic region of s2m Delta. The annotation and chemical shifts of nucleotide A735 are highlighted in blue. (B) 4D-HMQC-NOESY-HMQC C1′H1′ plane of A735. By transferring the aromatic chemical shifts (blue box) to the 4D a ¹H, ¹³C HSQC-like plane of the C1′H1′ region is displayed. (C) Overview of relevant magnetization transfers and secondary structure. (D) Overlay of the ¹H, ¹³C HSQC (ribose C1′H1′ region) of s2m Delta with the 4D plane of nucleotide A735. The resonance assignment for nucleotide A735 is highlighted in red. The resonance assignment of all nucleotides is annotated and the notation of nucleotides corresponds to the position in the genome −29,000.