Fig. 6: The N-terminal disordered region regulates the RNA-binding properties of LARP6 through a composite mechanism.
From: An intrinsically disordered region mediates RNA-binding selectivity and cellular activities of LARP6
a Overlay of the normalised Kratky plots obtained from the SEC-SAXS data analysis of recombinant LARP6 La-module, with or without P1 RNA (1:2 protein:RNA molar ratio). The comparison of plots indicates a conformational rearrangement of the La-module upon P1 RNA binding, leading to a quasi-globular locked conformation of the LaM and the RRM1. Full data sets in presence of RNA are reported in Supplementary Fig. 6b. b Overlay of the P(r) distance distribution functions of recombinant LARP6 La-module, with or without P1 RNA (1:2 molar ratio). The overall extension in the P(r) distance distributions is compatible with part of the P1 RNA elongating the shape of the complex. c Overlay of the normalised Kratky plots obtained from the SEC-SAXS data analysis of recombinant LARP6 NTD, with or without P1 RNA (1:2 molar ratio). The comparison of plots shows small conformational rearrangements to the NTD upon RNA-binding. Full data sets in the presence of RNA are reported in Supplementary Fig. 6c. d Overlay of the P(r) distance distribution functions of recombinant LARP6 NTD, with or without P1 RNA (1:2 molar ratio). The comparison of plots shows minor conformational rearrangements to the NTD upon RNA-binding. e Zoom-in of the overlay of 1H-15N TROSY NMR spectra obtained after adding P1 RNA into 15N-labelled LARP6 NTD. The region reports the window of 1H-resonances attributable to the flexible/unstructured NTR. Few peaks were perturbed (see grey arrows) upon RNA addition, indicating that the NTR only minorly engages with the RNA. Full spectra are reported in Supplementary Fig. 6e. f Per-residue CSP of the NTD resonances upon P1 RNA addition. Residues in both the La-module and the NTR are affected (SD: standard deviation). g R2 relaxation rates of the NTR region in isolation, when tethered to the La-module in both apo and CTNNA1 P1-RNA bound states. Relaxation rates were determined from exponential least-squares fitting of peak volumes. Error bars indicate mean ± SD, estimated from n = 100 cycles of Monte Carlo simulation and refitting.
