Prediction of the structural similarity between spermidine/putrescine-binding protein and maltose-binding protein

A structural similarity between spermidine/putrescine-binding protein and maltose-binding protein has been predicted by a sequence-structure compatibility method. The sequence alignment obtained by this method revealed a consensus sequence motif located on the surface loop between the first alpha-helix and the second beta-strand, and the further analysis identified a similar motif in iron-binding protein. The conservation of this motif among certain bacterial periplasmic binding proteins suggests a common functional role for this region as well as an evolutionary relationship between them.