RNA stores tau reversibly in complex coacervates
(A-C) Continuous wave electron paramagnetic resonance (cw EPR) spectra obtained at room temperature of 500 μM Δtau187-SL in droplets formed with 1.5 mg/ml poly(A) RNA (blue in A) and 1.5 mg/ml tRNA (green in B) is unaltered from solution before adding RNA (red in A and B). Cw EPR line shape upon adding 125 μM heparin (black in C) show dramatic line broadening (compared to red in C). Double electron-electron resonance (DEER) of Δtau187-SL2 in droplets formed with 1.5 mg/ml poly(A) RNA (blue in D) and 1.5 mg/ml tRNA (green in E), as well as upon incubation with 137.5 μM heparin (black in F) compared to Δtau187-SL2 in solution (red in D-F). The numerical data are included in S1 Data.