Part of the tripartite ATP-independent periplasmic (TRAP) transport system involved in the uptake of lactate. This protein specifically binds L-lactate. Homodimer. The complex comprises the extracytoplasmic solute receptor protein TTHA0766, and the two putative transmembrane proteins TTHA0767 and TTHA0768. Belongs to the bacterial solute-binding protein 7 family.