Substrate binding domain of Thermus thermophilus GluBP (TtGluBP) of TAXI family of the tripartite ATP-independent periplasmic transporters; contains the type 2 periplasmic binding protein fold.
This subgroup includes TtGluBP of TAXI-TRAP family and closely related proteins. TRAP transporters are comprised of an SBP (substrate-binding protein) and two unequally sized integral membrane components. Although TtGluBP is predicted to be an L-glutamate and/or an L-glutamine-binding protein, the substrate spectrum of TAXI proteins remains to be defined. A sequence-homology search also shows that TtGluBP shares low sequence homology with putative immunogenic proteins of uncharacterized function.