Fig. 4.

ATP-bound Hsp70 monomers assemble as antiparallel dimers in solution as determined by small-angle X-ray scattering. A, χ2-ranked fitting of Hsp70 dimeric crystal structures (PDB codes with indicated chains) and homology-based Hsp70 dimer model (see Experimental Procedures) to the SAXS experimental data obtained for Hsp70-T204A mutant at two concentrations. Fitting to the experimental scattering curves was performed using CRYSOL ATSAS v.2.8.3. B, CRYSOL fit of Hsp70 ATP dimer atomic model. Simulated scattering data of dimeric Hsp70 atomic model (red) is fitted to experimentally obtained solution scattering showing overall good fit with χ2 = 1.1. C, Atomic model of Hsp70 ATP-dependent dimer, developed as described in Experimental Procedures. NBD is highlighted in yellow, SBDβ in marine and SBDα in green. N- and C-terminal unstructured regions of the model are omitted from the figure. The image was created in PyMOL.