α-helix bundle mechanical stability.

<p>(a) Schematic representation of talin rod bundles and (b) α-catenin domains. Vinculin binding sites colored in blue. (c) Cartoon illustration of R9, where Cα of N-terminal residue colored in blue and Cα of C-terminal residue is red. (d) SMD water box and (e) smAFMsetup, that were used for end-to-end stretching of studied proteins. Unfolding force profiles of talin rod R9 in (f) SMD and (g) smAFM experiments, where after collapsing of 5-helix bundle (peak I) the stable 3-helix intermediate was found (peak II). α-helix bundles used in unfolding experiments highlighted with yellow.