Figure 4.

The monomers of apo-CcpA and its DNA complex (PDB code 1rzr) are shown based on superposition of the N-subdomains (Nsub). In the apo-CcpA structure (dark colours), contacts are made to a symmetry-related mate of the DNA-binding domain (Dbd*, orange) at the same area where the corepressor Hpr binds in the DNA complex (light colours). The residues of the N-subdomain involved and discussed in the text are shown in ball-and-stick representation (blue). Also note the major movement of the DNA-binding domain by a rotation of 136°.