Fig. 3
From: A proline switch explains kinetic heterogeneity in a coupled folding and binding reaction
Isomerization of Pro20 is the cause of kinetic heterogeneity. a Model of NCBD (PDB entry 2KKJ)23, with helix-terminating proline residues highlighted in turquoise. b Dwell-time distributions for the bound state of surface-immobilized ACTR for all NCBD variants, with single-exponential (dashed line, light red residuals) and double-exponential fits (solid line, dark red residuals) and the fitted rates indicated. Dwell times below 12 ms are too short to be identified reliably by the Viterbi algorithm (Supplementary Fig. 6) and are hence omitted. MLH analysis results are compiled in Supplementary Table 2. c Normalized ratio of chi-squared as an indicator for the quality of single- and double-exponential fits in b, showing variants containing Pro20 in dark green and those with Pro20 exchanged by Ala in light green. d Schematic representation of acceptor-labeled ACTR (blue) binding to surface-immobilized donor-labeled NCBD P20A (orange). e Corresponding representative single-molecule time trace (donor emission green, acceptor emission red). f Dwell-time distributions and residuals for ACTR binding to and dissociating from surface-immobilized NCBD P20A, with single-exponential fits (solid lines). g 2D histogram of 〈τon〉 and 〈τoff〉 from 113 time traces showing a single kinetic cluster. h Two-state kinetic model used to analyze the time traces of NCBD P20A
