The mkdom and XDOM programs have been used to analyze the domain organizations of the NBD proteins. The analysis revealed two types of organization in Treponema pallidum : (1) the dimeric ATP-binding proteins (NBD-NBD) (e.g. TP0321, TP0685, TP0300 and TP0838) and (2) the isolated NBD.

Black box: Walker A motif

Red box: signature and Walker B motif