Fig. 2
From: Mechanical architecture and folding of E. coli type 1 pilus domains
Mechanical stability of individual Fim domains. a Schematic view of a force-extension experiment with a polyprotein. I91 domains flank the Fim domain under study and the whole molecule is held under force between the cantilever and the gold surface. b Force-extension traces of the four Fim proteins. The color lines represent the fitting of the unfolding of the Fim domains with the worm-like chain model. From top to bottom are shown the traces of FimA (magenta), FimF (blue), FimG (green), and FimH, which shows seven peaks since it is composed of a pilin domain (orange) and a lectin domain (brown). c Contour length increment (ΔLc) vs force scatter plots of the four Fim proteins. FimA, FimF, and FimG disulfide-bonded domains (indicated with the subscript S-S) show lower ΔLc and higher unfolding forces than when they are reduced (SH-SH subscript). FimH shows two populations that correspond with the pilin (FimHP) and the lectin (FimHL) domains. (FimAS-S n = 43, FimASH-SH n = 68, FimFS-S n = 79, FimFSH-SH n = 40, FimGS-S n = 110, FimGSH-SH n = 65, FimHP n = 51, FimHL n = 26). d Unfolding forces of pilus domains in their oxidized (Ox) and reduced (Red) state. Histogram represents the average value of the data points shown in (c) and the error bars the SEM (mean ± SEM)
