Fig. 4.

ClfA behaves as a force-sensitive molecular switch. (A) SMFS data obtained by recording force-distance curves in PBS between Fg tips (PEG chemistry) and three different cells from a model L. lactis strain expressing ClfA [L. lactis ClfA⁽⁺⁾ cells]. (Scale bars: 100 nm.) (B) Strength of the ClfA–Fg interaction measured at increasing loading rates (LRs) on L. lactis ClfA⁽⁺⁾ cells (4,452 adhesive events from 10 cells). All adhesion peaks were analyzed to take into account all possible interactions. (C) The probability of forming strong bonds increases with the LR. From the data shown in B, discrete ranges of LRs were binned, and the force distributions were plotted as histograms (SI Appendix, Fig. S6). Shown here are the forces observed for low, medium, and high LRs.