Fig. 2
AMF-SMFS characterization of the ApCPEB PLD monomer. a Schematic cartoon of pFS-2 vector using I27 as a carrier (gray), hosting ApCPEB PLD (yellow) as a guest. Ubi molecules used as single-molecule markers are represented in black. The polyprotein encoded by pFS-2 contains a random coil region (a fragment of titin, N2B, gray line), acting as a spacer to overcome the noisy proximal region of the force-extension recordings. b Representative force-extensions recordings. Traces in yellow correspond to NM events. M events, in red, show different mechanical stability (Fu) and increased contour length (ΔLc) values. “b”+“c” values complete the length of the fully stretched ApCPEB PLD. c ΔLc and Fu histograms for polyproteins carrying ApCPEB PLD reveal a rich conformational polymorphism in terms of ΔLc (top panel) and Fu (bottom panel), ranging from NM events (yellow bars) to M events (red bars, n = 145). In the presence of QBP1, the mechanical conformational polymorphism is lowered, while SCR has no apparent effect (QBP1; n = 186, SCR; n = 144)