Figure 2.

PolyP disrupts long-range interactions and compacts the PRR and MTBR of tau. Histograms from smFRET measurements of 2N4R (upper panels) and 2N3R (lower panels) tau in the absence (dark gray and dashed line; left axis) and presence (light gray and solid line; right axis) of 20 μM polyP₃₀₀. Labeling positions are chosen to probe the entire protein (C17–C433: a and b), the N-terminal domain (C17–C149: c and d), the PRR and MTBR (C149–C372: e and f), and the C-terminal domain (C372–C433: g and h). The numbers are the labeling positions by residue number based on 2N4R. Tau schematics above each histogram represent the isoform and labeling positions. Measurements carried out in PIE-FRET as described in the Materials and Methods are marked with an asterisk (dark/light gray in the absence/presence of polyP) on the top left corner. At least three separate measurements of each condition/construct were made. The histograms shown are representative. The statistical analysis of repeat measurements is given in Table S1. To see this figure in color, go online.