Figure 2. Overview of the solution structure of hnRNP A1 RRM2 bound to 5´-UCAGUU-3´ RNA.

(A) NMR ensemble. Overlay of the 20 final structures superimposed on the backbone of the structured part (103-112, 115-139, 144-187) and represented as a ribbon trace (N, Cα, C´). The not-well-defined N- and C-terminal residues as well as nucleotides U₁, U₅ and U₆ are omitted for a better overview. The RNA is shown in stick representation with the carbon atoms in yellow, nitrogen in blue, phosphate in orange and oxygen in red. (B) Cartoon drawing of a representative structure of the NMR ensemble. Residues with important roles in RNA binding are shown as sticks, with the carbon atom in green. All other atoms have the same color code as in panel A. (C–E) Close-up views of each single nucleotide recognition by hnRNP A1 RRM2. Representation and colors are similar to panel B. Residues with important roles in RNA binding are labeled.

DOI: http://dx.doi.org/10.7554/eLife.25736.005

Figure 2—figure supplement 1. Overview of the titration of 5´-UCAGUU-3´to hnRNP A1 RRM2.

(A) NMR titration of hnRNP A1 RRM2 with the 5´-UCAGUU-3´ RNA. Overlay of a 2D (¹⁵N,¹H)-HSQC of the free form in blue and the bound form at a 1:1 ratio in red. Aliased peaks are colored in cyan (free) and orange (bound). Residues with large chemical shift perturbations are highlighted with an arrow. (B) Plot of the combined backbone NH chemical shift perturbation of hnRNP A1 RRM2 upon binding to the 5´-UCAGUU-3´ RNA. Residues with large chemical shift perturbations are labeled on the histogram. (*) corresponds to missing amide signals in either the free or bound form. Secondary structure elements are depicted above the histogram.

DOI: http://dx.doi.org/10.7554/eLife.25736.006

Figure 2—figure supplement 2. The side chain of methionine 186 drives most of the C-terminal helix α3 folding upon RNA-binding.

(A) Overlay of (¹⁵N,¹H)-HSQCs of free RRM2 (in blue) and of RRM2 bound to 1.0 eq of 5´-UCAGUU-3´ RNA (in red). In addition to chemical shift changes due to direct contact with the RNA, residues at the C-terminal end of RRM2 experience large chemical shift perturbation due to the structuration of a C-terminal α-helix (Ser182-Ala189). (B) Overlay of (¹⁵N,¹H)-HSQCs of free RRM2-M186A variant (in blue) and of RRM2-M186A bound to 1.0 eq of 5´-UCAGUU-3´ RNA (in red). Although binding on the β-sheet surface still occurs (see residues Gly110, Gly111 and Met137), the structuration of the C-terminal helix α3 is extremely perturbed (signals of residues Ser182-Ala189 do not appear at the same position in the spectrum).

DOI: http://dx.doi.org/10.7554/eLife.25736.007