Fig. 2.

N-to-C unfolding of titin^I27 domains by ClpXP or ClpAP. (A and B) Distributions of ClpXP preunfolding dwell times for V15P titin^I27 (A) or wild-type titin^I27 (B). Orange symbols are dwells before nonterminal unfolding events; green symbols are dwells before terminal unfolding events. (C and D) Distributions of ClpAP preunfolding dwell times for V15P titin^I27 (C) and wild-type titin^I27 (D). Cyan symbols are dwells before nonterminal unfolding events; green symbols are dwells before terminal unfolding events. Fits of cumulative frequency distributions to single exponentials are shown in solid black lines and to double exponentials in dashed lines. The residual plots for individual fits are shown. Solid red lines are fitted distributions for C-to-N degradation taken from Cordova et al. (14) or Olivares et al. (15). Single-molecule C-to-N degradation of wild-type titin^I27 by ClpAP has not been characterized. (E) Distributions of terminal dwells for ClpXP (orange; n = 90) and ClpAP (blue; n = 56) traces. The solid lines are single-exponential fits.