Fig. 5.

Schematics of nucleotide and force-induced conformational changes of the SBD in the absence or presence of peptide substrate. The Hsp70 chaperone DnaK undergoes large ATP-dependent conformational changes leading to the open state of the SBD (green color corresponds to the β-subdomain, red color corresponds to the α-subdomain). During this transition, the interface breaks and α/β subdomains move apart. In our approach, the interface is mechanically broken and subdomains are physically separated, which leads to the force-induced open states. The states shown in squared brackets []* are not observed directly but can be postulated based on the reference states obtained from α^Fβ^F and β^F fluctuations.