Ab initio models of the different constructs of TraB and of LvhB4. Two orientations, rotated along the long axis, of the best models generated by the program GASBOR of TraBFL (A); TraBNT (B); TraBCT (C) and LvhB4 (D). All TraB models (FL; NT; CT) were generated with an imposed P2 symmetry. The black cross and the dashed-line indicate the P2 symmetry axis between the two monomers in the dimeric model. The double arrow-head dotted-line indicates the maximum dimension (Dmax) of each model.