Fig. 3: The NPM1 IDR retains disorder and experiences attenuated backbone motions within the condensed phase with p14^ARF.

A The 2D ¹H-¹⁵N TROSY-HSQC spectrum of [¹³C,¹⁵N]-NPM1 within the p14^ARF-NPM1 condensed phase displays resonances from the NPM1 IDR. B Linear net charge per residue (LNCPR) for the NPM1 IDR. Nuclear spin relaxation for [²H,¹⁵N]-NPM1 in solution (blue scatter points) and condensed phase [¹³C,¹⁵N]-NPM1 (red scatter points), including C ¹H-¹⁵N heteronuclear NOEs, D R₁, and E R₂ transverse relaxation, which shows a restriction of NPM1 IDR backbone motions on the ps-ns timescale. The error bars for R₁ and R₂ transverse relaxation plots represent the standard errors from curve fitting, as described in Methods. F The contributions from exchange broadening, R_ex. G ¹⁵N-CPMG relaxation dispersion profiles for condensed [¹³C,¹⁵N]-NPM1 measured at 800 MHz, including A186, T199, and A201, fit to a two-state model. Scatter points represent the decay rates, and the error bars represent the estimated systematic error, as described in Methods. H Schematic describing NPM1 IDR conformational exchange within condensates with p14^ARF.