Bug (Bordetella uptake gene) protein family of periplasmic solute-binding receptors; contains the type 2 periplasmic binding fold.
The Bug (Bordetella uptake gene) protein family is a large family of periplasmic solute-binding (PBP) proteins present in a number of bacterial species, but mainly in proteobacteria. In eubacteria, at least three families of periplasmic binding-protein dependent transporters are known: the ATP-binding cassette (ABC) transporters, the tripartite ATP-independent periplasmic transporters, and the tripartite tricarboxylate transporters (TTT). Bug proteins are the PBP components of the 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.
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