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 Haemophilus ducreyi: (1) the
dimeric ATP-binding proteins (NBD-NBD) (e.g. HD224), (2) the membrane/ATP-binding domain associations (MSD-NBD) (e.g. HD1630) (NBD-MSD) (e.g. HD1019), and (3) the isolated NBD.
Black box: Walker A motif
Red box: signature and Walker B motif