Fig. 1: Structures of SARS-CoV-2 RNA genome stem-loop (SL) SL2 and SL3 elements and their binding ability to human TIA1 protein.
a Architecture of TIA1 RNA recognition motif (RRM) RRM2 and RRM3 domains. RRM2 and RRM3 adopt the canonical βαββαβ RRM fold composed of four anti-parallel β-sheets (β1, β2, β3, and β4) and two α-helices (α1 and α2). A non-canonical helix α0 in the flexible linker is preceded to RRM3. Secondary and 3D structures for (b) SL2 and (c) SL3 RNA elements. Stem, hairpin loop, and terminal loop in 5′-/3′-end are colored by green, blue, and orange, respectively. All 3D structures are predicted by IsRNA2 model. The NMR solution structure (1st model) for SARS-CoV SL232 (PDB id: 2l6i) is given in gray in (b). Other possible 3D conformations for SL3 element predicted by IsRNA2 are shown in light gray in (c). Positions from the whole SARS-CoV-2 RNA genome for SL2 and SL3 elements are provided in parentheses. d EMSA results (left) and the binding curve (right) show TIA1 bound to 5′ end Cy3-labeled SL2 + SL3 RNA. The binding curves for individual (e) SL2 and (f) SL3 RNA element with TIA1 protein. From d to f, the Kd values were calculated from the EMSA image quantification from three independent experiments. Data are presented as mean ± SD. Source data are provided as a Source Data file.
