Figure 1.

Schematic representation of the multiple segmental labeling approaches. (A) First step of the two-step ligation: segments G1-A8 RNA (red) and G9-U28 RNA (blue/brown) are hybridized to a complementary DNA splint (purple) and ligated by T4 DNA ligase. (B) Second step of the two-step ligation: segment G1-U28 RNA is hybridized to segment G29-C61 (green) and ligated by T4 RNA ligase 1 into the full ε-DHBV RNA. (C) One-pot ligation: segments G1-A8, G9-U28 and G29-C61 are putatively preassembled to resemble the full ε-DHBV RNA and ligated by T4 RNA ligase 1. Brown uridine residues of the G9-U28 RNA segment are ¹³C₉/¹⁵N₂/²H_{(1′, 3′, 4′, 5′, 5′′)}-stable isotope labeled.