Fig. 1. DIC and NMR visualization of ATP in modulating LLPS of TDP-43 PLD.

a Schematic representation of WT and seven mutants of TDP-43 PLD with their pI values indicated. b Turbidity (absorption at 600 nm) of TDP-43 PLD at 15 μM in the presence of ATP at different molar ratios in 10 mM sodium phosphate buffer at pH 5.5 and 7.0, as well as at 7.5 μM at pH 5.5. c DIC images of TDP-43 PLD at 15 μM in the presence of ATP at different molar ratios in the same buffer respective at pH 5.5 and 7.0. d DIC images of TDP-43 PLD at 7.5 μM in the presence of ATP at different molar ratios at pH 5.5. e ¹H-¹⁵N NMR HSQC spectra of the ¹⁵N-labeled TDP-43 PLD at 15 μM in the absence (blue) and in the presence of ATP at a molar ratio of 1:1000 (red) in 10 mM sodium phosphate buffer (pH 5.5). f Chemical shift difference (CSD) of TDP-43 PLD between the free state and in the presence ATP at 1:100 (blue) and 1:1000 (red), respectively. The green line is used to indicate the value: average + STD at the ATP ratio of 1:1000. The residues with CSD values >average + SD are defined as significantly perturbed residues.