TAtT is a family of one component, the T-component, of a sub-set of TRAP-Ts or Tripartite ATP-independent periplasmic transporters. TRAP-Ts are bacterial transport systems implicated in the import of small molecules into the cytoplasm in bacteria. They are all periplasmic lipoproteins. TatT consists of a 13-alpha-helical fold containing cryptic tetratricopeptide repeat motifs (cTPRs) and encompassing a pore, ie is a water-soluble trimer whose protomers are each perforated by a pore. It forms a complex with a P component, and a putative ligand-binding cleft of TatPT aligns with the pore of TatT. Family TatPT is represented by some members of pfam03480.