The mkdom and XDOM programs have been used to analyze the domain organizations of the NBD proteins. The analysis revealed three types of organization in Chlamydia trachomatis: (1) the dimeric ATP-binding proteins (NBD-NBD) (e.g. CT348), (2) the membrane/ATP-binding domain associations (MSD-NBD) (e.g.CT264), and (3) the isolated NBD.

Black box: Walker A motif

Red box: signature and Walker B motif