Fig. 3: The specific interaction of Npl3 RRM1 with RNA.
From: RNA recognition by Npl3p reveals U2 snRNA-binding compatible with a chaperone role during splicing
A Modified Scaffold independent analysis performed by titrating Npl3 RRM1 with 6mer ssDNAs. N is for any nucleotide (A, T, C or G). The normalized CSP represents the sum of combined chemical shift perturbations of non-overlapping peaks upon binding of the ssDNA to the RRM1 at a 1:1 ratio. The value was then normalized to the one obtained with the 5´-NNCCNN-3´ ssDNA. Source data are provided as a Source Data file. B ITC measurement performed in duplicate with Npl3 RRM1 and the AUCCAA RNA. C Overlay of TOCSY spectra recorded with unlabeled RNA in the absence (in blue) and in the presence of Npl3 RRM1 at a 1:1 ratio (in red). Arrows represent the movement of the H5-H6 cross peaks for U2, C3, and C4 in different directions upon protein binding. D Overlay of 1H-15N HSQC spectra recorded during the NMR titration of 15N labeled Npl3 RRM1 with increasing amount of unlabeled 5´-AUCCAA-3´ RNA. The titration was performed at 40 °C in the RRM1 NMR buffer. The peaks corresponding to the free and RNA-bound protein states (RNA:protein ratio of 1:1) are colored in blue and red, respectively. Black arrows indicate the most prominent chemical shift perturbations observed upon RNA binding. E Representation of the combined chemical shift perturbations of Npl3 RRM1 amide residues upon binding to the 5´-AUCCAA-3´ RNA at a ratio of 1:1 as a function of residue number. The corresponding secondary structure elements are represented at the top of the graph. The highest chemical shift perturbations annotated in D are indicated. The largest shift is observed for Lys194 with a value of 1.36 ppm. Source data are provided as a Source Data file.
