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 Porphyromonas gingivalis: (1) the dimeric ATP-binding proteins (NBD-NBD) (e.g. PG1923, PG1929, and PG1084), (2) the membrane/ATP-binding domain associations (MSD-NBD) (e.g., PG1497, PG1048, and PG1049), and (3) the isolated NBD.

Black box: Walker A, B motif

Green box: MSD domain