Aspartic acid transporter of Bug (Bordetella uptake gene) protein family; contains the type 2 periplasmic binding fold.
The Bug (Bordetella uptake gene) protein family is a large family of periplasmic solute-binding (PBP) receptors present in a number of bacterial species, but mainly in proteobacteria. Bug proteins are the PBP components of the tripartite carboxylate transporters (TTT). Their expansive expansion in proteobacteria indicates a large functional diversity. The best studied examples are Bordetella pertussis BugD, which is an aspartic acid transporter, and BugE, which is glutamate transporter.