Fig. 6.

The RecX protein (red) consists of three domains, where each domain contains three α-helices⁴⁰. The structural similarity of each of the three domains has suggested a gene triplication. The DinI protein (yellow) is a single domain, containing two α-helices and a single β-sheet³⁶. Two of the three RecX helices superimpose quite well on the two helices in DinI, raising the possibility of homology for this RecA-binding domain. At the bottom DinI helix containing residues 17-31 is superimposed on the RecX helix containing residues 81-90, while at the top the DinI helix containing residues 57-73 is superimposed on the RecX helix containing residues 63-76.