Assembly of TraB-domain SAXS models, reconstituted with the program GASBOR. (A) The TraBNT (blue) and TraBCT (red) models are superimposed onto the TraBFL model (transparent yellow). (B) The TraBNT model is superimposed onto the TraBFL model. (C) The TraBCT model is superimposed onto the TraBFL model. (D and E) Cartoons representing the domain organisation of TraB deduced from the SAXS models. Two possibilities for the TraBFL monomer are shown, with dimer 1 (D) and dimer 2 (E). The inset shows the TraBFL monomer. In the dimer, one monomer is represented in plain lines without transparency, the other monomer is represented in dotted-lines and transparency. The black cross and the dashed-line both indicate the P2 symmetry axis of the dimeric models. The SAXS models are shown in two orientations, with a 90° degrees angle rotation along the long axis.